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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2012	Feb. 28, 2013	Jun. 29, 2012
Document and Entity Information
Entity Registrant Name	Verastem, Inc.
Entity Central Index Key	0001526119
Document Type	10-K
Document Period End Date	Dec. 31, 2012
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Public Float			$ 89,675,000
Entity Common Stock, Shares Outstanding		21,152,465
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	FY

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 10,096	$ 20,954
Short-term investments	46,480	26,857
Prepaid expenses and other current assets	506	130
Total current assets	57,082	47,941
Property and equipment, net	811	709
Long-term investments	34,944	8,994
Other assets		1,307
Restricted cash	86	86
Total assets	92,923	59,037
Current liabilities:
Accounts payable	1,848	2,273
Accrued expenses	551	873
Total current liabilities	2,399	3,146
Deferred rent	38	74
Liability for shares subject to repurchase	20	36
Obligation to issue warrant		406
Commitments and contingencies ( Note 10 )
Redeemable convertible preferred stock		68,141
Stockholders' (deficit) equity
Convertible preferred stock, $0.0001 par value; no and 5,000 shares authorized at December 31,2011 and 2012, respectively, no shares issued and outstanding
Common stock, $0.0001 par value; 53,093 and 100,000 shares authorized at December 31, 2011 and 2012, respectively, 1,559 and 20,364 shares issued and outstanding at December 31, 2011 and 2012, respectively	2	1
Additional paid-in capital	136,893	1,702
Accumulated other comprehensive (loss) income	22	(2)
Deficit accumulated during the development stage	(46,451)	(14,467)
Total stockholders' (deficit) equity	90,466	(12,766)
Total liabilities, redeemable convertible preferred stock and stockholders' (deficit) equity	$ 92,923	$ 59,037

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares shares in Thousands	Dec. 31, 2012	Dec. 31, 2011
CONSOLIDATED BALANCE SHEETS
Convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	5,000	0
Convertible preferred stock, shares issued	0	0
Convertible preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	100,000	53,093
Common stock, shares issued	20,364	1,559
Common stock, shares outstanding	20,364	1,559

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	5 Months Ended	12 Months Ended		29 Months Ended
	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
Operating expenses:
Research and development	$ 400	$ 21,712	$ 9,883	$ 31,995
General and administrative	384	10,518	3,815	14,717
Total operating expenses	784	32,230	13,698	46,712
Loss from operations	(784)	(32,230)	(13,698)	(46,712)
Interest income		246	15	261
Net loss	(784)	(31,984)	(13,683)	(46,451)
Accretion of preferred stock	(2)	(6)	(32)	(40)
Net loss applicable to common stockholders	$ (786)	$ (31,990)	$ (13,715)	$ (46,491)
Net loss per share applicable to common stockholders-basic and diluted (in dollars per share)	$ (0.91)	$ (1.70)	$ (10.59)	$ (5.44)
Weighted-average number of common shares used in net loss per share applicable to common stockholders-basic and diluted (in shares)	850	18,765	1,295	8,547
Net loss	$ (784)	$ (31,984)	$ (13,683)	$ (46,451)
Unrealized (losses) gains on available-for-sale securities		24	(2)	22
Comprehensive loss	$ (784)	$ (31,960)	$ (13,685)	$ (46,429)

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' (DEFICIT) EQUITY - USD ($) $ in Thousands	Total	Redeemable convertible preferred stock	Redeemable convertible preferred stock Series A redeemable convertible preferred stock	Redeemable convertible preferred stock Series B redeemable convertible preferred stock	Redeemable convertible preferred stock Series C redeemable convertible preferred stock	Common stock	Additional paid-in capital	Accumulated other comprehensive loss	Deficit accumulated during the development stage
Balance at Dec. 31, 2010	$ (687)	$ 3,923				$ 1	$ 96		$ (784)
Balance (in shares) at Dec. 31, 2010		4,000,000				1,014,876
Increase (Decrease) in Stockholders' Equity
Net loss	(13,683)								(13,683)
Unrealized gain (loss) on investments	(2)							$ (2)
Issuance of redeemable convertible preferred stock			$ 12,000	$ 31,937	$ 20,249
Issuance of redeemable convertible preferred stock (in shares)			12,000,000	16,025,000	9,067,825
Accretion of redeemable convertible preferred stock to redemption value	(32)	$ 32					(32)
Vesting of restricted stock	3						3
Vesting of restricted stock (in shares)						543,712
Stock-based compensation expense	1,635						1,635
Balance at Dec. 31, 2011	$ (12,766)	$ 68,141				$ 1	1,702	(2)	(14,467)
Balance (in shares) at Dec. 31, 2011	1,559,000	41,092,825				1,558,588
Increase (Decrease) in Stockholders' Equity
Net loss	$ (31,984)								(31,984)
Unrealized gain (loss) on investments	24							24
Accretion of redeemable convertible preferred stock to redemption value	(6)	$ 6					(6)
Conversion of redeemable convertible preferred stock into common stock	68,147	$ (68,147)				$ 1	68,146
Conversion of redeemable convertible preferred stock into common stock (in shares)		(41,092,825)				11,740,794
Issuance of common stock, net of issuance costs of $1,984	56,838						56,838
Issuance of common stock, net of issuance costs of $1,984 (in shares)						6,325,000
Issuance of common stock in exchange for license	1,957						1,957
Issuance of common stock in exchange for license (in shares)						192,012
Vesting of restricted stock	16						16
Vesting of restricted stock (in shares)						542,421
Issuance of common stock resulting from exercise of stock options	3						3
Issuance of common stock resulting from exercise of stock options (in shares)						5,395
Obligation to issue a warrant	837						837
Stock-based compensation expense	7,400						7,400
Balance at Dec. 31, 2012	$ 90,466					$ 2	$ 136,893	$ 22	$ (46,451)
Balance (in shares) at Dec. 31, 2012	20,364,000					20,364,210

CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' (DEFICIT) EQUITY (Parenthetical) - USD ($) $ in Thousands	5 Months Ended	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011
Issuance of common stock, issuance costs		$ 1,984
Redeemable convertible preferred stock \| Series A redeemable convertible preferred stock
Issuance of redeemable convertible preferred stock, offering costs	$ 79
Redeemable convertible preferred stock \| Series B redeemable convertible preferred stock
Issuance of redeemable convertible preferred stock, offering costs			$ 113
Redeemable convertible preferred stock \| Series C redeemable convertible preferred stock
Issuance of redeemable convertible preferred stock, offering costs			$ 153

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	5 Months Ended	12 Months Ended		29 Months Ended
	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
CONSOLIDATED STATEMENTS OF CASH FLOWS
Net loss	$ (784)	$ (31,984)	$ (13,683)	$ (46,451)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization		207	83	290
Stock-based compensation expense	52	7,400	1,635	9,087
Common stock issued in exchange for license	46	1,957		2,003
Obligation to issue a warrant in exchange for license			439	439
Change in fair value of obligation to issue a warrant		431	(33)	398
Changing in operating assets and liabilities:
Prepaid expenses and other current assets	(12)	(376)	(118)	(506)
Accounts payable	279	(425)	1,994	1,848
Accrued expenses and deferred rent	89	189	311	589
Net cash used in operating activities	(330)	(22,601)	(9,372)	(32,303)
Investing activities
Purchases of property and equipment	(8)	(310)	(785)	(1,103)
Purchases of investments		(154,028)	(35,851)	(189,879)
Maturities of investments		108,479		108,479
Increase in restricted cash			(86)	(86)
Net cash used in investing activities	(8)	(45,859)	(36,722)	(82,589)
Financing activities
Proceeds from the issuance of redeemable convertible preferred stock	3,921		64,186	68,107
Proceeds from the exercise of stock options		3		3
Net proceeds (costs) from the issuance of common stock and restricted common stock	1	57,599	(722)	56,878
Net cash provided by financing activities	3,922	57,602	63,464	124,988
Increase (decrease) in cash and cash equivalents	3,584	(10,858)	17,370	10,096
Cash and cash equivalents at beginning of period		20,954	3,584
Cash and cash equivalents at end of period	3,584	10,096	20,954	10,096
Supplemental disclosure of non-cash financial activity
Accretion of redeemable convertible preferred stock to redemption value	$ 2	6	$ 32	40
Conversion of redeemable convertible preferred stock upon initial public offering		68,148		68,148
Reclassification of obligation to issue warrant from liabilities to equity		$ 837		$ 837

Nature of business	12 Months Ended
Nature of business	Dec. 31, 2012
Nature of business
Nature of business	1. Nature of business Verastem, Inc. (the "Company"), incorporated on August 4, 2010 as a Delaware corporation, is a biopharmaceutical company focused on discovering and developing proprietary small molecule drugs targeting cancer stem cells along with proprietary companion diagnostics. The Company's operations to date have been limited to organizing and staffing the Company, business planning, raising capital, acquiring and developing its technology, identifying potential product candidates and undertaking preclinical studies of its most advanced product candidates. The Company has not commenced its planned principal operations. Accordingly, the Company is considered to be in the development stage as defined in Financial Accounting Standards Board Accounting Standards Codification Topic 915, Development Stage Entities. The Company is subject to a number of risks similar to other life science companies in the development stage, including, but not limited to, the need to obtain adequate additional funding, possible failure of preclinical testing or clinical trials, inability to obtain marketing approval of product candidates, competitors developing new technological innovations, market acceptance of the Company's products and protection of proprietary technology. If the Company does not successfully commercialize any of its product candidates, it will be unable to generate product revenue or achieve profitability. As of December 31, 2012, the Company had a deficit accumulated during the development stage of $46.5 million. The Company expects to continue to incur operating losses in future periods. The Company had cash, cash equivalents and investments of $91.5 million as of December 31, 2012. The Company believes that its existing cash, cash equivalents and investments will be sufficient to fund its current operating plan and capital expenditure requirements for at least the next 12 months. Initial public offering In February 2012, the Company closed the initial public offering (IPO) of its common stock pursuant to a registration statement on Form S-1, as amended. An aggregate of 6,325,000 shares of common stock registered under the registration statement were sold at a price of $10.00 per share, including the over-allotment option. Net proceeds of the IPO were $56.8 million. All shares of the Company's Redeemable Convertible Preferred Stock were converted into 11,740,794 shares of common stock as part of the IPO. Reverse stock split In January 2012, the Company's board of directors and stockholders approved a one-for-3.5 reverse stock split of the Company's common stock. The reverse stock split became effective on January 10, 2012. All share and per share amounts in the financial statements have been retroactively adjusted for all periods presented to give effect to the reverse stock split, including reclassifying an amount equal to the reduction in par value to additional paid-in capital.

Significant accounting policies

12 Months Ended

Dec. 31, 2012

Significant accounting policies

Significant accounting policies

2. Significant accounting policies

Basis of consolidation

The information reported within the Company's financial statements from August 4, 2010 to December 31, 2011 was based solely on the accounts of Verastem, Inc. Effective December 2012, Verastem Securities Company was incorporated as a wholly owned subsidiary of the Company. Effective December 2012, all financial information presented has been consolidated and includes the accounts of the Company and its wholly owned subsidiary. All intercompany balances and transactions have been eliminated in consolidation.

Use of estimates

The preparation of the Company's financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, management evaluates its estimates, including estimates related to accruals and stock-based compensation expense. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable. Actual results could differ from such estimates.

Prior to becoming a public company in February 2012, the Company utilized significant estimates and assumptions in determining the fair value of its common stock. The Company granted stock options at exercise prices not less than the fair market value of its common stock as determined by the board of directors, with input from management. The board of directors determined the estimated fair value of the Company's common stock based on a number of objective and subjective factors, including external market conditions affecting the biotechnology industry sector and the prices at which the Company sold shares of redeemable convertible preferred stock, the superior rights and preferences of securities senior to the Company's common stock at the time and the likelihood of achieving a liquidity event, such as an IPO or sale of the Company.

The Company utilized various valuation methodologies in accordance with the framework of the American Institute of Certified Public Accountants Technical Practice Aid, Valuation of Privately-Held Company Equity Securities Issued as Compensation, to estimate the fair value of its common stock. The methodologies included an asset-based approach and the current value method for the Company's initial common stock valuation as of November 30, 2010, the option pricing method utilizing the reverse backsolve method to estimate the Company's underlying equity value as of July 31, 2011 and a methodology that determined an estimated value under an IPO scenario and a sale scenario based upon an assessment of the probability of occurrence of each scenario as of September 30, 2011, November 17, 2011, and December 31, 2011. Each valuation methodology included estimates and assumptions that required the Company's judgment. These estimates included assumptions regarding future performance, including the successful completion of preclinical studies and clinical trials and the time to completing an IPO or sale. Significant changes to the key assumptions used in the valuations could result in different fair values of common stock at each valuation date.

Segment and geographic information

Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating segment, which is the business of developing drugs that target cancer stem cells. The Company operates in only one geographic area.

Cash and cash equivalents

The Company considers all highly liquid investments with an original or remaining maturity of three months or less at the date of purchase to be cash equivalents. Cash equivalents consist of money market funds, U.S. agency notes and corporate bonds. Cash equivalents are reported at fair value.

Fair value of financial instruments

The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. The fair value hierarchy prioritizes valuation inputs based on the observable nature of those inputs. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs:


Level 1 inputs		Quoted prices in active markets for identical assets or liabilities
Level 2 inputs		Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly
Level 3 inputs		Unobservable inputs that reflect the Company's own assumptions about the assumptions market participants would use in pricing the asset or liability

The following table presents information about the Company's financial assets that have been measured at fair value at December 31, 2012 and indicates the fair value hierarchy of the valuation inputs utilized to determine fair value (in thousands).

Description	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)

Financial assets
Cash equivalents	$	8,171	$	8,171	$	—	$	—
Short-term investments		46,480		—		46,480		—
Long-term investments		34,944		—		34,944		—

Total financial assets	$	89,595	$	8,171	$	81,424	$	—

The following table presents information about the Company's financial assets that have been measured at fair value at December 31, 2011 and indicates the fair value hierarchy of the valuation inputs utilized to determine such fair value (in thousands).

Description	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)

Financial assets
Cash equivalents	$	4,102	$	3,102	$	1,000	$	—
Short-term investments		26,857		—		26,857		—
Long-term investments		8,994		—		8,994		—

Total financial assets	$	39,953	$	3,102	$	36,851	$	—

Financial liabilities
Obligation to issue warrant	$	406	$	—	$	—	$	406

Total financial liabilities	$	406	$	—	$	—	$	406

In connection with the license agreement with Poniard Pharmaceuticals Inc. (Poniard), the Company is obligated to issue a warrant to Poniard for the purchase of the Company's common stock upon the first patient dosing using a product licensed under the agreement with Poniard; such warrant will have a three year term from the date of issuance. Prior to the Company's initial public offering, the exercise price of the warrant would have been equal to the fair value of the common stock on the date of the most recent preferred stock financing prior to the issuance of the warrant. Upon the completion of the Company's initial public offering in January 2012, the exercise price of the warrant will be equal to the average closing price of the Company's common stock during the five trading days preceding the issuance of the warrant.

Prior to January 2012, the obligation to issue the warrant was a level 3 liability because its value measurement was based, in part, on significant inputs not observed in the market and reflects the Company's assumptions as to the expected warrant exercise price and the expected volatility of the Company's common stock. The obligation to issue the warrant was initially recorded at fair value and, prior to the Company's initial public offering, was revalued at the end of each reporting period, with the change in the fair value reported in research and development expense within the statement of operations. Upon the completion of the Company's initial public offering, the obligation to issue the warrant met the definition of an equity-classified derivative instrument since the remaining variable inputs were consistent with those in a fixed for fixed forward option agreement, and was therefore revalued as of January 26, 2012 with the change in fair value reported in research and development expense within the statement of operations. The fair value of the obligation to issue the warrant was then reclassified from liabilities to additional paid-in-capital on the Company's consolidated balance sheet. The Company will reassess the equity classification of the obligation to issue the warrant upon a change in facts and circumstances in future reporting periods.

As of December 31, 2011, the most recent issuance of the Company's Preferred Stock had been the issuance of the Series C Preferred Stock in November 2011. The Company estimated the value of the obligation to issue the warrant using a probability-weighted scenario analysis that incorporated the probability of the completion of an initial public offering. The analysis included estimating the stock price on each measurement date assuming that achievement of the milestone would be 100% probable. The estimated stock price contingent upon milestone achievement was determined by analyzing the post-announcement returns for public companies that progressed to Phase 1 clinical trials. The following inputs were used to determine the fair value of the obligation to issue the warrant:

				December 31, 2011

	January 26, 2012			December 31, 2011
	January 26, 2012			Non-IPO			IPO
Exercise price	$	11.09		$	6.86		$	10.00
Estimated stock price contingent upon milestone achievement	$	12.60		$	3.22		$	8.54
Expected term		4.0 years			4.1 years			4.1 years
Volatility		75	%		70	%		70	%
Dividend yield		0.00	%		0.00	%		0.00	%
Risk-free rate		0.54	%		0.60	%		0.60	%
Probability of achieving milestone		80	%		80	%		80	%
Probability of scenario		100	%		20	%		80	%

As of December 31, 2011, the fair value of the obligation to issue the warrant was recorded at $406,000. As a result of the change in inputs to the valuation model, the fair value of the obligation to issue the warrant increased by $431,000 to $837,000 at January 26, 2012. Reasonable changes in the assumptions used to calculate the fair value of the obligation to issue the warrant would not result in significant changes in the fair value.

Investments

Investments and cash equivalents consist of investments in money market accounts, government-sponsored enterprise securities and commercial paper of publicly traded companies secured by the U.S. government that are classified as available-for-sale pursuant to Accounting Standards Codification (ASC) 320, Investments—Debt and Equity Securities. The Company classifies investments available to fund current operations as current assets on its balance sheets. Investments are classified as long-term assets on the balance sheets if (i) the Company has the intent and ability to hold the investments for a period of at least one year and (ii) the contractual maturity date of the investments is greater than one year. Investments are carried at fair value with unrealized gains and losses included as a component of accumulated other comprehensive loss, which is a separate component of stockholders' equity (deficit), until such gains and losses are realized. The fair value of these securities is based on quoted prices for identical or similar assets. If a decline in the fair value is considered other-than-temporary, based on available evidence, the unrealized loss is transferred from other comprehensive loss to the statement of operations. There were no other-than-temporary declines in fair value of short-term or long-term investments for the period from August 4, 2010 (inception) to December 31, 2010, the year ended December 31, 2011 and the year ended December 31, 2012. Realized gains and losses are determined using the specific identification method and are included in interest income in the statement of operations. There were no realized gains or losses recognized for the period from August 4, 2010 (inception) to December 31, 2010, the year ended December 31, 2011 and the year ended December 31, 2012.

The Company reviews investments for other-than-temporary impairment whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment's carrying amount is not recoverable within a reasonable period of time. To determine whether an impairment is other-than-temporary, the Company considers the intent to sell, or whether it is more likely than not that the Company will be required to sell, the investment before recovery of the investment's amortized cost basis. Evidence considered in this assessment includes reasons for the impairment, compliance with the Company's investment policy, the severity and the duration of the impairment and changes in value subsequent to year end. As of December 31, 2011 and 2012, there were no investments with a fair value that was significantly lower than the amortized cost basis or any investments that had been in an unrealized loss position for a significant period.

As of December 31, 2012, cash, cash equivalents and investments included (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value

Cash and cash equivalents:
Cash and money market accounts	$	10,096	$	—	$	—		$	10,096
Government-sponsored enterprise securities		—		—		—			—

Total cash and cash equivalents	$	10,096	$	—	$	—		$	10,096
Investments:
Government-sponsored enterprise securities (due within 1 year)	$	44,480	$	14	$	(3	)	$	44,491
Government-sponsored enterprise securities (due within 1 - 2 years)		36,920		14		(1	)		36,933

Total investments	$	81,400	$	28	$	(4	)	$	81,424

Total cash, cash equivalents, and investments	$	91,496	$	28	$	(4	)	$	91,520

As of December 31, 2011, cash, cash equivalents and investments included (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value

Cash and cash equivalents:
Cash and money market accounts	$	19,954	$	—	$	—		$	19,954
Government-sponsored enterprise securities		1,000		—		—			1,000

Total cash and cash equivalents	$	20,954	$	—	$	—		$	20,954
Investments:
Government-sponsored enterprise securities (due within 1 year)	$	10,900	$	2	$	(1	)	$	10,901
Government-sponsored enterprise securities (due within 1 - 2 years)		8,998		1		(5	)		8,994
Commercial paper secured by the U.S. government (due within 1 year)		15,954		3		(1	)		15,956

Total investments	$	35,852	$	6	$	(7	)	$	35,851

Total cash, cash equivalents, and investments	$	56,806	$	6	$	(7	)	$	56,805

Concentrations of credit risk and off-balance sheet risk

Cash and cash equivalents and investments are financial instruments that potentially subject the Company to concentrations of credit risk. As of December 31, 2012, the Company's cash, cash equivalents and investments were deposited at two financial institutions. The Company maintains its cash and cash equivalents and investments with high quality, accredited financial institutions and, accordingly, the Company believes it is not exposed to any significant credit risk on these funds. The Company has no significant off-balance sheet concentrations of credit risk, such as foreign currency exchange contracts, option contracts or other hedging arrangements.

Property and equipment

Property and equipment consists of laboratory equipment, office furniture, and computer equipment. Expenditures for repairs and maintenance are recorded to expense as incurred, whereas major betterments are capitalized as additions to property and equipment. Depreciation is calculated using the straight-line method over the following estimated useful lives of the assets:


Laboratory equipment		5 years
Furniture		5 years
Computer equipment		3 years

Upon retirement or sale, the cost of the disposed asset and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is recognized.

The Company reviews its long-lived assets for impairment whenever events or changes in business circumstances indicate that the carrying value of assets may not be recoverable. Recoverability is measured by comparison of the asset's book value to future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book value of the assets exceed their fair value, which is measured based on the projected discounted future net cash flows arising from the assets. No such impairment losses have been recorded through December 31, 2012.

Organizational costs

All organizational costs have been expensed as incurred.

Research and development costs

The Company expenses research and development costs to operations as incurred. Research and development expenses consist of costs associated with research activities, including drug discovery efforts and the development of therapeutic product candidates and companion diagnostics. The Company accounts for nonrefundable advance payments for goods and services that will be used in future research and development activities as expenses when the service has been performed or when the goods have been received rather than when the payment is made. Research and development expenses consist of:

•

employee-related expenses, including salaries, benefits, travel and stock-based compensation expense;

•

external research and development expenses incurred under arrangements with third parties, such as contract research organizations, or CROs, manufacturing organizations and consultants, including the scientific advisory board;

•

license fees; and

•

facilities, depreciation and other expenses, which include direct and allocated expenses for rent and maintenance of facilities, depreciation of equipment, and laboratory supplies.

Stock-based compensation

The Company expenses the fair value of employee stock options over the requisite service period, which is the vesting period. Compensation expense is measured using the fair value of the award at the grant date, net of estimated forfeitures, and is adjusted annually to reflect actual forfeitures. The grant date fair value of each stock-based award is estimated using the Black-Scholes option pricing model and is expensed on a straight-line basis over the vesting period.

Stock-based awards issued to nonemployees, including directors for non-board related services, are accounted for based on the fair value of such services received or of the equity instruments issued, whichever is more reliably measured. Stock option awards are revalued at each vesting date using the Black-Scholes option pricing model and are expensed on a straight-line basis over the vesting period.

Prior to becoming a public company, the exercise prices for options granted were set by the board of directors, the members of which have extensive experience in the life science industry, with input from management of the Company, based on the board's determination of fair value of the common stock at the time of the grants. The Company performed contemporaneous valuations, utilizing a combination of valuation methods described in the American Institute of Certified Public Accountants Technical Practice Aid, Valuation of Privately-Held-Company Equity Securities Issued as Compensation, (Practice Aid).

Income taxes

The Company accounts for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Tax benefits are recognized when it is more likely than not that a tax position will be sustained during an audit. Deferred tax assets are reduced by a valuation allowance if current evidence indicates that it is considered more likely than not that these benefits will not be realized.

Net loss per share

Basic and diluted net loss per common share is calculated by dividing net loss applicable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. The Company's potentially dilutive shares, which include redeemable convertible preferred stock, outstanding stock options, restricted stock units, and unvested restricted stock are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive.

The following potentially dilutive securities were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect:



		Years Ended December 31,
		2011		2012
Preferred Stock	1,142,857		11,740,794		—	—
Outstanding stock options	177,143		405,141		1,424,241	1,424,241
Restricted stock units	—		—		899,204	899,204
Unvested restricted stock	2,008,926		1,434,734		747,000	747,000

	3,328,926		13,580,669		3,070,445	3,070,445

Property and equipment

12 Months Ended

Dec. 31, 2012

Property and equipment

Property and equipment

3. Property and equipment

Property and equipment and related accumulated depreciation are as follows (in thousands):

	December 31, 2011			December 31, 2012

Laboratory equipment	$	721		$	1,017
Computer equipment		27			27
Furniture		44			44

		792			1,088
Less: accumulated depreciation		(83	)		(277	)

	$	709		$	811

Total depreciation expenses amounted to $0, $83,000, $207,000 and $290,000 for the period from August 4, 2010 (inception) to December 31, 2010, the year ended December 31, 2011, the year ended December 31, 2012 and the period from August 4, 2010 (inception) to December 31, 2012, respectively.

- Definition

The entire disclosure for long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. This disclosure may include property plant and equipment accounting policies and methodology, a schedule of property, plant and equipment gross, additions, deletions, transfers and other changes, depreciation, depletion and amortization expense, net, accumulated depreciation, depletion and amortization expense and useful lives, income statement disclosures, assets held for sale and public utility disclosures.

+ References + Details

Prepaid expenses and other current assets

12 Months Ended

Dec. 31, 2012

Prepaid expenses and other current assets

Prepaid expenses and other current assets

4. Prepaid expenses and other current assets

Prepaid expenses and other current assets consist of the following (in thousands):

	December 31, 2011		December 31, 2012

Prepaid contract research organization costs	$	—	$	274
Interest receivable		53		161
Prepaid other		77		71

	$	130	$	506

Accrued expenses

12 Months Ended

Dec. 31, 2012

Accrued expenses

Accrued expenses

5. Accrued expenses

Accrued expenses are as follows (in thousands):

	December 31,

	2011		2012
Professional fees	$	520	$	183
Compensation and related benefits		86		173
Contract research organization costs		217		69
Consulting		—		36
Deferred rent		27		36
Other		23		54

	$	873	$	551

Redeemable convertible preferred stock

12 Months Ended

Dec. 31, 2012

Redeemable convertible preferred stock

Redeemable convertible preferred stock

6. Redeemable convertible preferred stock

On February 1, 2012, immediately prior to the closing of the Company's initial public offering, all outstanding shares of the Company's redeemable convertible preferred stock were converted into 11,740,794 shares of common stock. As of December 31, 2012, the Company does not have any redeemable convertible preferred stock authorized, issued, or outstanding.

Prior to the closing of the initial public offering, the Company's redeemable preferred stock consisted of the following (in thousands except share and per share amounts):

	As of December 31,

	2011		2012
Series A redeemable convertible preferred stock, $0.0001 par value; 16,000 and no shares authorized, 16,000 and no shares issued and outstanding at December 31, 2011 and 2012, respectively (Liquidation preference of $16,000 as of December 31, 2011)		15,939		—
Series B redeemable convertible preferred stock, $0.0001 par value; 16,025 and no shares authorized, 16,025 and no shares issued and outstanding at December 31, 2011 and 2012, respectively (Liquidation preference of $32,050 as of December 31, 2011)		31,948		—
Series C redeemable convertible preferred stock, $0.0001 par value; 9,068 and no shares authorized,9,068 and no shares issued and outstanding at December 31, 2011 and 2012, respectively (Liquidation preference of $20,403 as of December 31, 2011)		20,254		—

	$	68,141	$	—

In November 2010, the Company sold 4 million shares of Series A redeemable convertible preferred stock (Series A Preferred Stock) at a price of $1.00 per share for gross proceeds of $4 million. In accordance with the terms of the Series A Stock Purchase Agreement, the Company sold an additional 12 million shares at $1.00 per share in a second subsequent closing. The Company incurred approximately $79,000 of issuance costs as part of the first closing of the Series A Preferred Stock. No additional issuance costs were incurred as part of the second closing.

In July 2011, the Company sold approximately 16 million shares of series B redeemable convertible preferred stock (Series B Preferred Stock) at a price of $2.00 per share for gross proceeds of approximately $32 million. The Company incurred approximately $113,000 of issuance costs as part of the closing of the Series B Preferred Stock.

In November 2011, the Company sold approximately 9.1 million shares of Series C redeemable convertible preferred stock (Series C Preferred Stock) at a price of $2.25 per share for gross proceeds of $20.4 million. The Company incurred approximately $153,000 of issuance costs as part of the closing of the Series C Preferred Stock. The issuance costs associated with the Series A Preferred Stock, Series B Preferred Stock and Series C Preferred Stock (collectively, the Preferred Stock) were accreted through the earliest redemption date.

The Company assessed the Preferred Stock for any beneficial conversion features or embedded derivatives that would require bifurcation from the Preferred Stock and receive separate accounting treatment. On the date of each issuance, the value of the common stock into which the Preferred Stock was convertible had a fair value less than the effective conversion price of the Preferred Stock and, as such, there was no intrinsic value on the respective commitment dates. No embedded derivatives were identified that would require bifurcation.

Common stock

12 Months Ended

Dec. 31, 2012

Common stock

Common stock

7. Common stock

As of December 31, 2012 and December 31, 2011, the Company had reserved the following shares of common stock for the potential conversion of outstanding Preferred Stock, the issuance of common stock for vested restricted stock units and the exercise of stock options (in thousands):



Series A Preferred Stock	4,571	—
Series B Preferred Stock	4,579	—
Series C Preferred Stock	2,591	—
Shares reserved under equity compensation plans	563	3,930

	12,304	3,930

Each share of common stock is entitled to one vote, subject to certain voting rights of the Preferred Stock as discussed in Note 6. The holders of the common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors, subject to the prior rights of the Preferred Stockholders.

- Definition

The entire disclosure for shareholders' equity, comprised of portions attributable to the parent entity and noncontrolling interest, if any, including other comprehensive income (as applicable). Including, but not limited to: (1) balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings; (2) accumulated balance for each classification of other comprehensive income and total amount of comprehensive income; (3) amount and nature of changes in separate accounts, including the number of shares authorized and outstanding, number of shares issued upon exercise and conversion, and for other comprehensive income, the adjustments for reclassifications to net income; (4) rights and privileges of each class of stock authorized; (5) basis of treasury stock, if other than cost, and amounts paid and accounting treatment for treasury stock purchased significantly in excess of market; (6) dividends paid or payable per share and in the aggregate for each class of stock for each period presented; (7) dividend restrictions and accumulated preferred dividends in arrears (in aggregate and per share amount); (8) retained earnings appropriations or restrictions, such as dividend restrictions; (9) impact of change in accounting principle, initial adoption of new accounting principle and correction of an error in previously issued financial statements; (10) shares held in trust for Employee Stock Ownership Plan (ESOP); (11) deferred compensation related to issuance of capital stock; (12) note received for issuance of stock; (13) unamortized discount on shares; (14) description, terms, and number of warrants or rights outstanding; (15) shares under subscription and subscription receivables, effective date of new retained earnings after quasi-reorganization and deficit eliminated by quasi-reorganization and, for a period of at least ten years after the effective date, the point in time from which the new retained dates; and (16) retroactive effective of subsequent change in capital structure.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=6228006&loc=d3e74512-122707

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187143-122770

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Section B
-Paragraph 7, 11A
-Chapter 1
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph d
-Article 4

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
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-Paragraph 29, 30, 31
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Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 20: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Article 4

Reference 21: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

Reference 22: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 3, 4, 5, 6, 7, 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 23: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

+ Details

Stock-based compensation

12 Months Ended

Dec. 31, 2012

Stock-based compensation

Stock-based compensation

8. Stock-based compensation

Stock-based compensation expense as reflected in the Company's consolidated statements of operations and comprehensive loss was as follows (in thousands):

	Period from August 4, 2010 (Inception) to December 31, 2010		Year Ended December 31,				Period from August 4, 2010 (Inception) to December 31, 2012

	Period from August 4, 2010 (Inception) to December 31, 2010		2011		2012		Period from August 4, 2010 (Inception) to December 31, 2012
Research and development	$	24	$	981	$	2,956	$	3,961
General and administrative		28		654		4,444		5,126

Total stock-based compensation expense	$	52	$	1,635	$	7,400	$	9,087

The Company maintains two equity compensation plans, the 2012 Incentive Plan (the "2012 Plan") and the 2010 Equity Incentive Plan (the "2010 Plan"). Terms of stock award agreements, including vesting requirements, are determined by the board of directors, subject to the provisions of the individual plans. To date, most options granted by the Company vest twenty five percent (25%) one year from vesting start date and seventy-five percent (75%) in equal installments over the subsequent twelve quarters (subject to acceleration of vesting in the event of certain change of control transactions) and are exercisable from the date of grant for a period of ten years.

2012 Incentive Plan

In December 2011, the Company adopted the 2012 Plan. The 2012 Plan became effective immediately upon the closing of the Company's IPO in February 2012. Upon effectiveness of the 2012 Plan, the Company ceased making awards under the 2010 Plan. The 2012 Plan allows the Company to grant awards for up to 3,428,571 shares of common stock plus the number of shares of common stock available for grant under the 2010 Plan as of the effectiveness of the 2012 Plan (which was an additional 30,101 shares) plus that number of shares of common stock related to awards outstanding under the 2010 Plan which terminate by expiration, forfeiture, cancellation or otherwise. The 2012 Plan includes an "evergreen provision" that allows for an annual increase in the number of shares of common stock available for issuance under the 2012 Plan. The annual increase will be added on the first day of each year beginning in 2013 and each subsequent anniversary until the expiration of the 2012 Plan, equal to the lowest of 1,285,714 shares of common stock, 4.0% of the number of shares of common stock outstanding and an amount determined by the board of directors. Awards under the 2012 Plan may include the following award types: incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock awards, restricted stock units (RSUs), other stock-based or cash-based awards and any combination of the foregoing. As of December 31, 2012, under the 2012 Plan, the Company has granted stock options for 1,039,714 shares of common stock, of which 8,328 have been forfeited and restricted stock units for 909,918 shares of common stock, of which 10,714 have been forfeited. The exercise price of each option has been equal to the closing price of a share of our common stock on the grant date.

2010 Equity Incentive Plan

In November 2010, the Company adopted the 2010 Plan, under which it was authorized to grant stock-based awards to purchase up to 404,762 shares of common stock to eligible employees, officers, directors and consultants. In March 2011, the 2010 Plan was amended to increase the aggregate number of shares of common stock available to be issued under the 2010 Plan to 571,242 shares of common stock. As of December 31, 2012, a total of 405,141 options and 256,000 restricted stock awards have been granted, 5,395 options have been exercised and 126,891 have been forfeited and repurchased, under the 2010 Plan. As of February 2012, the Company ceased making awards under the 2010 Plan and the remaining 30,101 shares available for future grants were added to the total number of shares reserved for issuance under the 2012 Plan. For options granted under the 2010 Plan, the exercise price equaled the estimated fair value of the common stock as determined by the board of directors on the date of grant.

Restricted common stock

In connection with the Company's formation, the founders purchased an aggregate of 2,857,138 shares of Company common stock at fair value on the date of issuance. The shares were issued subject to restricted stock agreements between the Company and each founder, which allow the Company, at its discretion, to repurchase unvested shares if the founder's relationship with the Company is terminated. Under these agreements, twenty five percent (25%) of the shares vested immediately, and the remaining seventy-five percent (75%) of shares vest ratably in quarterly installments over the subsequent four years.

The Company records stock-based compensation expense for the common stock subject to repurchase, or restricted common stock grants, based on the grant date intrinsic value for employees and the vesting date intrinsic value for non-employees. All of the restricted shares were issued at fair value. The Company recorded stock-based compensation expense associated with restricted common stock grants of approximately $51,000, $1.4 million, $3.3 million and $4.8 million for the period August 4, 2010 (inception) to December 31, 2010, the year ended December 31, 2011, the year ended December 31, 2012 and the period from August 4, 2010 (inception) to December 31, 2012, respectively.

A summary of the Company's restricted stock activity and related information is as follows:

			Weighted-average fair value per share

Unvested at December 31, 2011	1,434,734		$	0.02530
Granted	—			—
Vested	(542,421	)		0.02920
Forfeited	(145,313	)		0.00035

Unvested at December 31, 2012	747,000		$	0.02730

The weighted-average grant date fair value of restricted stock granted during the period from August 4, 2010 (inception) to December 31, 2010, the year ended December 31, 2011 and the period from August 4, 2010 (inception) to December 31, 2012 was $0.00035, $0.28 and $0.02 per share, respectively. No restricted stock was granted during the year ended December 31, 2012. As of December 31, 2012, there was $4.2 million of total unrecognized stock-based compensation expense related to unvested restricted stock. The Company expects to recognize this expense over a remaining weighted-average period of 1.75 years.

Restricted stock units

A summary of the Company's RSUs as of December 31, 2012 and changes during the year ended December 31, 2012 is as follows (in thousands, except per share data):

			Weighted- average grant date fair value per share

Unvested at December 31, 2011	—		$	—
Granted	909,918			10.62
Vested	(77,479	)		9.68
Cancelled	(10,714	)		11.10

Unvested at December 31, 2012	899,204		$	10.70

As of December 31, 2012, there was $6.5 million of total unrecognized stock-based compensation expense related to unvested RSUs granted under the 2012 Plan. The expense is expected to be recognized over a weighted-average period of 3.0 years.

During 2012, the Company issued a restricted stock unit for 103,306 shares to an employee. The award vests up to 25% per year based on the achievement of stated objectives. The objectives related to 2012 were modified in December 2012 and the Company recorded expense of $126,000 in connection with the modification.

Stock Options

A summary of the Company's stock option activity and related information follows:

			Weighted-average exercise price per share

Outstanding at December 31, 2011	405,141		$	0.75
Granted	1,039,714			9.25
Exercised	(5,395	)		0.56
Cancelled	(15,219	)		6.50

Outstanding at December 31, 2012	1,424,241			6.90	9.3	3,451

Vested at December 31, 2012	384,712			6.00	9.0	1,343

Vested and expected to vest at December 31, 2012(1)	1,382,496		$	6.87	9.3	3,415

(1): This represents the number of vested options as of December 31, 2012, plus the number of unvested options expected to vest as of December 31, 2012, based on the unvested options at December 31, 2012, adjusted for the estimated forfeiture rate.

The fair value of each employee stock option was estimated at the date of grant using a Black-Scholes option-pricing model with the following assumptions:



			Year Ended December 31,
			2011	2012
Risk-free interest rate	2.0	%	1.1% - 2.7%	0.8% - 1.7%
Volatility	67	%	69% - 70%	70% - 77%
Dividend yield	—		—	—
Expected term (years)	6.1		6.25	5.3 - 6.1

The Company uses the simplified method as prescribed by the Securities and Exchange Commission Staff Accounting Bulletin Topic 14.D.2 to calculate the expected term as it does not have sufficient historical exercise data to provide a reasonable basis upon which to estimate the expected term for options granted to employees. The expected term is applied to the stock option grant group as a whole, as the Company does not expect substantially different exercise or post-vesting termination behavior among its employee population. The computation of expected volatility is based on the historical volatility of a representative group of public biotechnology and life sciences companies with similar characteristics to the Company, including early stage of product development and therapeutic focus. Subsequent to the initial public offering, the Company began to use a blended volatility rate comprised of its own historical volatility and that of the representative group of companies. The risk-free interest rate is based on a treasury instrument whose term is consistent with the expected term of the stock options. Management assesses expected forfeitures based on the experience of the Company coupled with comparison to data from the representative group of companies and recognizes compensation costs only for those equity awards expected to vest.

For the period from August 4, 2010 (inception) to December 31, 2010 the Company did not recognize any stock-based compensation for employee stock option grants. The Company recorded stock-based compensation expense of $19,000 for the year ended December 31, 2011, and $1.6 million for the year ended December 31, 2012 and the period from August 4, 2010 (inception) to December 31, 2012, associated with employee stock options. The weighted-average grant date fair value of options granted in the period from August 4, 2010 (inception) to December 31, 2010, the year ended December 31, 2011, the year ended December 31, 2012 and the period from August 4, 2010 (inception) to December 31, 2012 was $0.18, $0.75, $6.03 and $4.48 per share, respectively.

At December 31, 2012, there was $5.4 million of total unrecognized compensation cost related to unvested stock options. As of December 31, 2012, the Company expects to recognize this cost over a remaining weighted-average period of 3.0 years.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 50
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5444-113901

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64, 65, A240
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 93-6
-Paragraph 53
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Income taxes

12 Months Ended

Dec. 31, 2012

Income taxes

Income taxes

9. Income taxes

As of December 31, 2012 the Company had federal net operating loss carryforwards of approximately $31.9 million and state net operating loss carryforwards of $31.9 million, which are available to reduce future taxable income. The Company also had federal tax credits of $358,000 and state tax credits of $229,000, which may be used to offset future tax liabilities. The net operating loss (NOL) and tax credit carryforwards will expire at various dates through 2032. Net operating loss and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities and may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant shareholders over a three-year period in excess of 50%, as defined under Sections 382 and 383 of the Internal Revenue Code, as well as similar state provisions. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years.

A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations follows:

	Year ended December 31,

	2011			2012
Income tax benefit using U.S. federal statutory rate		34.00	%		34.00	%
State income taxes, net of federal benefit		4.78	%		4.61	%
Research and development tax credits		1.65	%		—	%
Permanent items		(4.78	)%		(5.96	)%
Change in the valuation allowance		(35.65	)%		(32.19	)%
Other		—	%		(0.46	)%

		—	%		—	%

The principal components of the Company's deferred tax assets are as follows (in thousands):

	December 31,

	2011			2012
Deferred tax assets:
Net operating loss carryforwards	$	4,562		$	12,532
Capitalized research and development		148			1,664
Research and development credits		385			508
Stock-based compensation		82			797
Other		20			(23	)

Gross deferred tax assets		5,197			15,478
Valuation allowance		(5,197	)		(15,478	)

Net deferred tax asset	$	—		$	—

The Company has recorded a valuation allowance against its deferred tax assets at December 31, 2012 because the Company's management believes that it is more likely than not that these assets will not be fully realized. The increase in the valuation allowance of $320,000, $4.9 million and $10.3 million in the period from August 4, 2010 (inception) to December 31, 2010, the years ended December 31, 2011 and 2012 primarily relates to the net loss incurred by the Company.

Upon inception, the Company adopted accounting guidance related to accounting for uncertainty in income taxes. The Company's reserves related to taxes are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is more likely than not to be realized following resolution of any potential contingencies present related to the tax benefit. Upon adoption, the Company recognized no material adjustment for unrecognized income tax benefits. As of the adoption date and through December 31, 2012, the Company had no unrecognized tax benefits or related interest and penalties accrued. The Company has not, as yet, conducted a study of research and development (R&D) credit carryforwards. This study may result in an adjustment to the Company's R&D credit carryforwards; however, until a study is completed and any adjustment is known, no amounts are being presented as an uncertain tax position. A full valuation allowance has been provided against the Company's R&D credits and, if an adjustment is required, this adjustment would be offset by an adjustment to the valuation allowance. Thus, there would be no impact to the consolidated balance sheet or statement of operations if an adjustment were required. The Company would recognize both accrued interest and penalties related to unrecognized benefits in income tax expense. The Company's uncertain tax positions are related to years that remain subject to examination by relevant tax authorities. Since the Company is in a loss carryforward position, the Company is generally subject to examination by the U.S. federal, state and local income tax authorities for all tax years in which a loss carryforward is available.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

+ Details

Commitments and contingencies

12 Months Ended

Dec. 31, 2012

Commitments and contingencies

Commitments and contingencies

10. Commitments and contingencies

From November 2010 through May 2011, the Company leased office space from a shareholder. There was no formal lease arrangement with the shareholder. Rent paid to the shareholder was $12,000, $34,000, and none for the period from August 4, 2010 (inception) to December 31, 2010, the year ended December 31, 2011 and the year ended December 31, 2012, respectively.

In May 2011, the Company entered into a non-cancelable operating lease for office and laboratory space, which expires October 31, 2014. The lease agreement provides for free rent for the first four months of the lease term and includes escalating rent payments. The rent expense is recorded on a straight-line basis over the lease term. The Company is also obligated to pay for certain operating costs and a proportional share of certain common area costs. The Company has the right to extend the lease for a two-year period. The annual rent for each additional year is determined annually at the then fair market rate. The Company secured a letter of credit for $86,000 in connection with the lease, which is included in restricted cash on the balance sheet. The minimum aggregate future lease commitments are as follows (in thousands):


2013		360
2014		307

	$	667

The Company recorded rent expense of $12,000, $251,000, $323,000 and $786,000 for the period from August 4, 2010 (inception) to December 31, 2010, the year ended December 31, 2011, the year ended December 31, 2012 and the period from August 4, 2010 (inception) to December 31, 2012, respectively.

Pursuant to the terms of various agreements, the Company may be required to pay various development, regulatory and commercial milestones. In addition, if any products related to these agreements are approved for sale, the Company may be required to pay significant royalties on future sales. The payment of these amounts, however, is contingent upon the occurrence of various future events, which have a high degree of uncertainty of occurring.

- Definition

The entire disclosure for commitments and contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6449706&loc=d3e16207-108621

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.25)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25287-109308

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 14
-Paragraph 3
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

License agreements	12 Months Ended
License agreements	Dec. 31, 2012
License agreements
License agreements	11. License agreements In October 2010, the Company entered into an exclusive license agreement, which was amended and restated in January 2012, with the Whitehead Institute for Biomedical Research (the Licensor) for certain intellectual property. The Company paid the Licensor an upfront license fee and reimbursed patent related fees and costs incurred by the Licensor and affiliates of the Licensor totaling $104,000 in the aggregate and issued 166,664 shares of common stock to the Licensor and entities and individuals affiliated with the Licensor. The fair value of the common stock was determined to be $0.28 per share, and the fair value was determined to be more readily determinable than the fair value of the license. As a result, the fair value of the shares of approximately $46,000 was recorded as research and development expense. Under the terms of the agreement, the Company also agreed to pay annual license maintenance fees, milestone payments, royalties as a percentage of net sales and a percentage of sublicense income the Company receives. Annual license maintenance fees are creditable against royalties earned during the same calendar year and are not material to the financial statements. Milestone payments are triggered upon the achievement of specified development, regulatory and commercialization milestones and are not creditable against royalties. Actual amounts due under the agreement will vary depending on the number of products developed, the type and development path of the products, and other related factors. Milestone payments could total up to $1.6 million. The Company may terminate the agreement at any time with 90 days' prior written notice. On December 16, 2011, the Company amended and restated an existing non-exclusive license agreement with the Licensor pursuant to which the Company obtained an exclusive license to certain intellectual property. The Company paid the Licensor an upfront license fee and agreed to make milestone payments of up to $825,000 upon the achievement of specified regulatory and commercialization milestones. In addition, the Company agreed to pay royalties as a percentage of net sales of licensed products. On November 17, 2011, the Company entered into an exclusive, worldwide license agreement with Poniard Pharmaceuticals, Inc. to develop, make, use and sell compounds and products covered by the licensed patent rights for the diagnosis, treatment, prevention or control of human diseases and conditions. Under the agreement, the Company paid an upfront license fee and agreed to pay $13.3 million upon the achievement of specified development and regulatory milestones. The Company also agreed to issue to Poniard a warrant to purchase 142,857 shares of common stock upon the first dosing of the first patient in a Phase 1 clinical trial of a licensed product. The exercise price of such warrant would be equal to the average closing price of the Company's common stock during the five trading days preceding such issue date. In addition, the Company agreed to pay royalties as a percentage of net sales of licensed products. The Company may terminate the agreement at any time with 90 days' prior written notice. On May 11, 2012, the Company acquired from SBio Pte Ltd (SBio), compounds identified as dual inhibitors of PI3K and mTOR, including related patent rights. Under the agreement, the Company paid SBio an upfront fee of $350,000 and has agreed to pay SBio milestone payments of up to an aggregate of approximately $21.0 million upon the achievement of specified development and regulatory milestones. In addition, the Company agreed to pay to SBio tiered, low to mid single digit royalties as a percentage of annual net sales of each product containing an acquired compound as an ingredient. The obligation to pay royalties continues on a product by product and country by country basis until the expiration of all acquired patent rights covering the product in such country. If the Company obtains a license from a third party in order to commercialize an acquired compound contained in a product in a particular country, then the Company may deduct up to 50% of the amount paid to such third party from the royalty payments that Company owes to SBio for such product. The deduction is subject to specified limitations, including that in no event will any such deduction reduce a royalty payment owed to SBio by more than 50% as a result of all such deductions in the aggregate. There were no ongoing clinical trials at the time of the acquisition of the compounds, and the compounds acquired do not have alternative future uses, nor have they reached a stage of technological feasibility. As no process or activities were acquired, the Company accounted for the transaction as an asset acquisition by recording the $350,000 payment made to SBio to research and development expense for the year ended December 31, 2012. On July 11, 2012, the Company entered into a license agreement with Pfizer Inc. (Pfizer), under which Pfizer granted the Company worldwide, exclusive rights to research, develop, manufacture and commercialize products containing certain of Pfizer's inhibitors of focal adhesion kinase (Products) for all therapeutic, diagnostic and prophylactic uses in humans. The Company is solely responsible, at its expense, for the clinical development of the Products, which is to be conducted in accordance with an agreed-upon development plan. The Company is also responsible for all manufacturing and commercialization activities at its own expense. Pfizer is required to provide the Company with an initial quantity of clinical supply of one of the Products for an agreed upon price. Under the agreement, the Company made a one-time cash payment to Pfizer in the amount of $1.5 million and issued to Pfizer 192,012 shares of its common stock. Pfizer is also eligible to receive up to $2 million in developmental milestones and up to an additional $125 million based on the successful attainment of regulatory and commercial sales milestones. Pfizer is also eligible to receive high single to mid double digit royalties on future net sales of Products. The Company's royalty obligations with respect to each Product in each country begin on the date of first commercial sale of the Product in that country, and end on the later of 10 years after the date of first commercial sale of the Product in that country or the date of expiration or abandonment of the last claim contained in any issued patent or patent application licensed by Pfizer to the Company that covers the Product in that country. The Company accounted for the license agreement as the licensing of in-process research and development with no alternative future use. Accordingly, the Company recorded research and development expense for the year ended December 31, 2012 associated with the cash payment of $1.5 million and the fair value of shares of common stock issued to Pfizer of $2.0 million.

Employee benefit plan	12 Months Ended
Employee benefit plan	Dec. 31, 2012
Employee benefit plan
Employee benefit plan	12. Employee benefit plan In June 2011, the Company adopted a 401(k) retirement and savings plan (the 401(k) Plan) covering all employees. The 401(k) Plan allows employees to make pre-tax or post-tax contributions up to the maximum allowable amount set by the IRS. Under the 401(k) Plan, the Company may make discretionary contributions as approved by the board of directors. The Company made contributions to the 401(k) Plan of $0, $46,000, $116,000 and $162,000 for the period from August 4, 2010 (inception) to December 31, 2010, the year ended December 31, 2011, the year ended December 31, 2012 and the period from August 4, 2010 (inception) to December 31, 2012, respectively.

- Definition

The entire disclosure for pension and other postretirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-URI http://asc.fasb.org/topic&trid=2235017

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Implementation Guide (Q and A)
-Number FAS88
-Paragraph 63
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 106
-Paragraph 518
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph a
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 03-2
-Paragraph 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 87
-Paragraph 264
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph q
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5
-Subparagraph h
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 8
-Subparagraph m
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 132R
-Paragraph 5, 6, 7, 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 158
-Paragraph 7, 21, 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS106-2
-Paragraph 20, 21, 22
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 30
-Paragraph 26
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Quarterly Financial Information (unaudited, in thousands, except per share data)

12 Months Ended

Dec. 31, 2012

Quarterly Financial Information (unaudited, in thousands, except per share data)

Quarterly Financial Information (unaudited, in thousands, except per share data)

13. Quarterly Financial Information (unaudited, in thousands, except per share data)

	First Quarter Ended March 31, 2012			Second Quarter Ended June 30, 2012			Third Quarter Ended September 30, 2012			Fourth Quarter Ended December 31, 2012

Operating expenses:
Research and development	$	4,803		$	4,683		$	8,132	(b)	$	4,094
General and administrative		2,125			2,213			2,298			3,882

Total operating expenses		6,928			6,896			10,430			7,976

Loss from operations		(6,928	)		(6,896	)		(10,430	)		(7,976	)
Interest income		57			71			63			55

Net loss	$	(6,871	)	$	(6,825	)	$	(10,367	)	$	(7,921	)

Net loss per share applicable to common stockholders-basic and diluted	$	(0.47	)	$	(0.34	)	$	(0.51	)	$	(0.39	)
Weighted average number of common shares used in net loss per share applicable to common stockholders-basic and diluted		14,693	(a)		19,863			20,160			20,309

	First Quarter Ended March 31, 2011			Second Quarter Ended June 30, 2011			Third Quarter Ended September 30, 2011			Fourth Quarter Ended December 31, 2011

Operating expenses:
Research and development	$	675		$	1,726		$	3,082		$	4,400
General and administrative		471			759			965			1,620

Total operating expenses		1,146			2,485			4,047			6,020

Loss from operations		(1,146	)		(2,485	)		(4,047	)		(6,020	)
Interest income		—			—			—			15

Net loss	$	(1,146	)	$	(2,485	)	$	(4,047	)	$	(6,005	)

Net loss per share applicable to common stockholders-basic and diluted	$	(1.06	)	$	(2.03	)	$	(2.98	)	$	(4.01	)
Weighted average number of common shares used in net loss per share applicable to common stockholders-basic and diluted		1,089			1,225			1,361			1,500

(a): In February 2012, the Company completed its initial public offering, which resulted in net proceeds of approximately $56.8 million from the issuance of 6,325,000 shares of common stock, which includes the sale of 825,000 shares under the underwriters' over-allotment option. In connection with the initial public offering, all of the outstanding shares of the Company's redeemable convertible preferred stock were converted into 11,740,794 of common stock.
(b): In the quarter ended September 30, 2012, the Company paid a license fee of $1.5 million in cash and issued 192,012 shares of the Company's common stock, which were valued at $2.0 million on the date of issuance.

The Company was incorporated on August 4, 2010; however, it did not commence operations until the fourth quarter of 2010. Activity incurred during the period from August 4, 2010 (inception) to September 30, 2010 is limited to organizational costs which were expensed when incurred.

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

+ References + Details

Subsequent events	12 Months Ended
Subsequent events	Dec. 31, 2012
Subsequent events
Subsequent events	14. Subsequent events The Company reviews all activity subsequent to year end but prior to the issuance of the consolidated financial statements for events that could require disclosure or that could impact the carrying value of assets or liabilities as of the balance sheet date. All significant subsequent events have been properly disclosed in the consolidated financial statements.

Significant accounting policies (Policies)

12 Months Ended

Dec. 31, 2012

Significant accounting policies

Basis of consolidation

Basis of consolidation

Use of estimates

Use of estimates

Segment and geographic information

Segment and geographic information

Cash and cash equivalents

Cash and cash equivalents

Fair value of financial instruments

Fair value of financial instruments


Level 1 inputs		Quoted prices in active markets for identical assets or liabilities
Level 2 inputs		Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly
Level 3 inputs		Unobservable inputs that reflect the Company's own assumptions about the assumptions market participants would use in pricing the asset or liability

Description	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)

Financial assets
Cash equivalents	$	8,171	$	8,171	$	—	$	—
Short-term investments		46,480		—		46,480		—
Long-term investments		34,944		—		34,944		—

Total financial assets	$	89,595	$	8,171	$	81,424	$	—

Description	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)

Financial assets
Cash equivalents	$	4,102	$	3,102	$	1,000	$	—
Short-term investments		26,857		—		26,857		—
Long-term investments		8,994		—		8,994		—

Total financial assets	$	39,953	$	3,102	$	36,851	$	—

Financial liabilities
Obligation to issue warrant	$	406	$	—	$	—	$	406

Total financial liabilities	$	406	$	—	$	—	$	406

				December 31, 2011

	January 26, 2012			December 31, 2011
	January 26, 2012			Non-IPO			IPO
Exercise price	$	11.09		$	6.86		$	10.00
Estimated stock price contingent upon milestone achievement	$	12.60		$	3.22		$	8.54
Expected term		4.0 years			4.1 years			4.1 years
Volatility		75	%		70	%		70	%
Dividend yield		0.00	%		0.00	%		0.00	%
Risk-free rate		0.54	%		0.60	%		0.60	%
Probability of achieving milestone		80	%		80	%		80	%
Probability of scenario		100	%		20	%		80	%

Investments

Investments

As of December 31, 2012, cash, cash equivalents and investments included (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value

Cash and cash equivalents:
Cash and money market accounts	$	10,096	$	—	$	—		$	10,096
Government-sponsored enterprise securities		—		—		—			—

Total cash and cash equivalents	$	10,096	$	—	$	—		$	10,096
Investments:
Government-sponsored enterprise securities (due within 1 year)	$	44,480	$	14	$	(3	)	$	44,491
Government-sponsored enterprise securities (due within 1 - 2 years)		36,920		14		(1	)		36,933

Total investments	$	81,400	$	28	$	(4	)	$	81,424

Total cash, cash equivalents, and investments	$	91,496	$	28	$	(4	)	$	91,520

As of December 31, 2011, cash, cash equivalents and investments included (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value

Cash and cash equivalents:
Cash and money market accounts	$	19,954	$	—	$	—		$	19,954
Government-sponsored enterprise securities		1,000		—		—			1,000

Total cash and cash equivalents	$	20,954	$	—	$	—		$	20,954
Investments:
Government-sponsored enterprise securities (due within 1 year)	$	10,900	$	2	$	(1	)	$	10,901
Government-sponsored enterprise securities (due within 1 - 2 years)		8,998		1		(5	)		8,994
Commercial paper secured by the U.S. government (due within 1 year)		15,954		3		(1	)		15,956

Total investments	$	35,852	$	6	$	(7	)	$	35,851

Total cash, cash equivalents, and investments	$	56,806	$	6	$	(7	)	$	56,805

Concentrations of credit risk and off-balance sheet risk

Concentrations of credit risk and off-balance sheet risk

Property and equipment

Property and equipment


Laboratory equipment		5 years
Furniture		5 years
Computer equipment		3 years

Upon retirement or sale, the cost of the disposed asset and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is recognized.

Organizational costs

Organizational costs

All organizational costs have been expensed as incurred.

Research and development costs

Research and development costs

•

employee-related expenses, including salaries, benefits, travel and stock-based compensation expense;

•

external research and development expenses incurred under arrangements with third parties, such as contract research organizations, or CROs, manufacturing organizations and consultants, including the scientific advisory board;

•

license fees; and

•

facilities, depreciation and other expenses, which include direct and allocated expenses for rent and maintenance of facilities, depreciation of equipment, and laboratory supplies.

Stock-based compensation

Stock-based compensation

Income taxes

Income taxes

Net loss per share

Net loss per share

The following potentially dilutive securities were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect:



		Years Ended December 31,
		2011		2012
Preferred Stock	1,142,857		11,740,794		—	—
Outstanding stock options	177,143		405,141		1,424,241	1,424,241
Restricted stock units	—		—		899,204	899,204
Unvested restricted stock	2,008,926		1,434,734		747,000	747,000

	3,328,926		13,580,669		3,070,445	3,070,445

Significant accounting policies (Tables)

12 Months Ended

Dec. 31, 2012

Significant accounting policies

Schedule of information about financial assets and liabilities measured at fair value

Description	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)

Financial assets
Cash equivalents	$	8,171	$	8,171	$	—	$	—
Short-term investments		46,480		—		46,480		—
Long-term investments		34,944		—		34,944		—

Total financial assets	$	89,595	$	8,171	$	81,424	$	—

Description	Total		Quoted prices in active markets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)

Financial assets
Cash equivalents	$	4,102	$	3,102	$	1,000	$	—
Short-term investments		26,857		—		26,857		—
Long-term investments		8,994		—		8,994		—

Total financial assets	$	39,953	$	3,102	$	36,851	$	—

Financial liabilities
Obligation to issue warrant	$	406	$	—	$	—	$	406

Total financial liabilities	$	406	$	—	$	—	$	406

Schedule of inputs used to determine the fair value of the obligation to issue the warrant

				December 31, 2011

	January 26, 2012			December 31, 2011
	January 26, 2012			Non-IPO			IPO
Exercise price	$	11.09		$	6.86		$	10.00
Estimated stock price contingent upon milestone achievement	$	12.60		$	3.22		$	8.54
Expected term		4.0 years			4.1 years			4.1 years
Volatility		75	%		70	%		70	%
Dividend yield		0.00	%		0.00	%		0.00	%
Risk-free rate		0.54	%		0.60	%		0.60	%
Probability of achieving milestone		80	%		80	%		80	%
Probability of scenario		100	%		20	%		80	%

Schedule of cash, cash equivalents and investments

As of December 31, 2012, cash, cash equivalents and investments included (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value

Cash and cash equivalents:
Cash and money market accounts	$	10,096	$	—	$	—		$	10,096
Government-sponsored enterprise securities		—		—		—			—

Total cash and cash equivalents	$	10,096	$	—	$	—		$	10,096
Investments:
Government-sponsored enterprise securities (due within 1 year)	$	44,480	$	14	$	(3	)	$	44,491
Government-sponsored enterprise securities (due within 1 - 2 years)		36,920		14		(1	)		36,933

Total investments	$	81,400	$	28	$	(4	)	$	81,424

Total cash, cash equivalents, and investments	$	91,496	$	28	$	(4	)	$	91,520

As of December 31, 2011, cash, cash equivalents and investments included (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value

Cash and cash equivalents:
Cash and money market accounts	$	19,954	$	—	$	—		$	19,954
Government-sponsored enterprise securities		1,000		—		—			1,000

Total cash and cash equivalents	$	20,954	$	—	$	—		$	20,954
Investments:
Government-sponsored enterprise securities (due within 1 year)	$	10,900	$	2	$	(1	)	$	10,901
Government-sponsored enterprise securities (due within 1 - 2 years)		8,998		1		(5	)		8,994
Commercial paper secured by the U.S. government (due within 1 year)		15,954		3		(1	)		15,956

Total investments	$	35,852	$	6	$	(7	)	$	35,851

Total cash, cash equivalents, and investments	$	56,806	$	6	$	(7	)	$	56,805

Schedule of estimated useful lives of the assets:


Laboratory equipment		5 years
Furniture		5 years
Computer equipment		3 years

Schedule of potentially anti-dilutive securities excluded from calculation of diluted net loss per share


		Years Ended December 31,
		2011		2012
Preferred Stock	1,142,857		11,740,794		—	—
Outstanding stock options	177,143		405,141		1,424,241	1,424,241
Restricted stock units	—		—		899,204	899,204
Unvested restricted stock	2,008,926		1,434,734		747,000	747,000

	3,328,926		13,580,669		3,070,445	3,070,445

- Definition

Tabular disclosure of assets, including [financial] instruments measured at fair value that are classified in stockholders' equity, if any, by class that are measured at fair value on a recurring and/or nonrecurring basis. The disclosures contemplated herein include the fair value measurements at the reporting date by the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3).

+ References + Details

Property and equipment (Tables)

12 Months Ended

Dec. 31, 2012

Property and equipment

Schedule of property equipment and related accumulated depreciation

Property and equipment and related accumulated depreciation are as follows (in thousands):

	December 31, 2011			December 31, 2012

Laboratory equipment	$	721		$	1,017
Computer equipment		27			27
Furniture		44			44

		792			1,088
Less: accumulated depreciation		(83	)		(277	)

	$	709		$	811

Prepaid expenses and other current assets (Tables)

12 Months Ended

Dec. 31, 2012

Prepaid expenses and other current assets

Schedule of prepaid expenses and other current assets

Prepaid expenses and other current assets consist of the following (in thousands):

	December 31, 2011		December 31, 2012

Prepaid contract research organization costs	$	—	$	274
Interest receivable		53		161
Prepaid other		77		71

	$	130	$	506

Accrued expenses (Tables)

12 Months Ended

Dec. 31, 2012

Accrued expenses

Schedule of accrued expenses

Accrued expenses are as follows (in thousands):

	December 31,

	2011		2012
Professional fees	$	520	$	183
Compensation and related benefits		86		173
Contract research organization costs		217		69
Consulting		—		36
Deferred rent		27		36
Other		23		54

	$	873	$	551

Redeemable convertible preferred stock (Tables)

12 Months Ended

Dec. 31, 2012

Redeemable convertible preferred stock

Schedule of redeemable preferred stock

Prior to the closing of the initial public offering, the Company's redeemable preferred stock consisted of the following (in thousands except share and per share amounts):

	As of December 31,

	2011		2012
Series A redeemable convertible preferred stock, $0.0001 par value; 16,000 and no shares authorized, 16,000 and no shares issued and outstanding at December 31, 2011 and 2012, respectively (Liquidation preference of $16,000 as of December 31, 2011)		15,939		—
Series B redeemable convertible preferred stock, $0.0001 par value; 16,025 and no shares authorized, 16,025 and no shares issued and outstanding at December 31, 2011 and 2012, respectively (Liquidation preference of $32,050 as of December 31, 2011)		31,948		—
Series C redeemable convertible preferred stock, $0.0001 par value; 9,068 and no shares authorized,9,068 and no shares issued and outstanding at December 31, 2011 and 2012, respectively (Liquidation preference of $20,403 as of December 31, 2011)		20,254		—

	$	68,141	$	—

- Definition

Tabular disclosure of temporary equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

+ References + Details

Common stock (Tables)

12 Months Ended

Dec. 31, 2012

Common stock

Schedule of shares of common stock reserved for the potential conversion of outstanding Preferred Stock, the issuance of common stock for vested restricted stock units and the exercise of stock options



Series A Preferred Stock	4,571	—
Series B Preferred Stock	4,579	—
Series C Preferred Stock	2,591	—
Shares reserved under equity compensation plans	563	3,930

	12,304	3,930

Stock-based compensation (Tables)

12 Months Ended

Dec. 31, 2012

Stock-based compensation

Schedule of stock-based compensation expense as reflected in the Company's consolidated statements of operations and comprehensive loss

Stock-based compensation expense as reflected in the Company's consolidated statements of operations and comprehensive loss was as follows (in thousands):

	Period from August 4, 2010 (Inception) to December 31, 2010		Year Ended December 31,				Period from August 4, 2010 (Inception) to December 31, 2012

	Period from August 4, 2010 (Inception) to December 31, 2010		2011		2012		Period from August 4, 2010 (Inception) to December 31, 2012
Research and development	$	24	$	981	$	2,956	$	3,961
General and administrative		28		654		4,444		5,126

Total stock-based compensation expense	$	52	$	1,635	$	7,400	$	9,087

Summary of unvested restricted stock activity and related information

			Weighted-average fair value per share

Unvested at December 31, 2011	1,434,734		$	0.02530
Granted	—			—
Vested	(542,421	)		0.02920
Forfeited	(145,313	)		0.00035

Unvested at December 31, 2012	747,000		$	0.02730

Summary of restricted stock units (RSUs)

A summary of the Company's RSUs as of December 31, 2012 and changes during the year ended December 31, 2012 is as follows (in thousands, except per share data):

			Weighted- average grant date fair value per share

Unvested at December 31, 2011	—		$	—
Granted	909,918			10.62
Vested	(77,479	)		9.68
Cancelled	(10,714	)		11.10

Unvested at December 31, 2012	899,204		$	10.70

Summary of stock option activity and related information

			Weighted-average exercise price per share

Outstanding at December 31, 2011	405,141		$	0.75
Granted	1,039,714			9.25
Exercised	(5,395	)		0.56
Cancelled	(15,219	)		6.50

Outstanding at December 31, 2012	1,424,241			6.90	9.3	3,451

Vested at December 31, 2012	384,712			6.00	9.0	1,343

Vested and expected to vest at December 31, 2012(1)	1,382,496		$	6.87	9.3	3,415

(1): This represents the number of vested options as of December 31, 2012, plus the number of unvested options expected to vest as of December 31, 2012, based on the unvested options at December 31, 2012, adjusted for the estimated forfeiture rate.

Schedule of assumptions used to estimate fair value of each stock-based award on grant date



			Year Ended December 31,
			2011	2012
Risk-free interest rate	2.0	%	1.1% - 2.7%	0.8% - 1.7%
Volatility	67	%	69% - 70%	70% - 77%
Dividend yield	—		—	—
Expected term (years)	6.1		6.25	5.3 - 6.1

- Definition

Tabular disclosure of the allocation of equity-based compensation costs to a given line item on the balance sheet and income statement for the period. This may include the reporting line for the costs and the amount capitalized and expensed.

+ References + Details

Income taxes (Tables)

12 Months Ended

Dec. 31, 2012

Income taxes

Schedule of reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations

	Year ended December 31,

	2011			2012
Income tax benefit using U.S. federal statutory rate		34.00	%		34.00	%
State income taxes, net of federal benefit		4.78	%		4.61	%
Research and development tax credits		1.65	%		—	%
Permanent items		(4.78	)%		(5.96	)%
Change in the valuation allowance		(35.65	)%		(32.19	)%
Other		—	%		(0.46	)%

		—	%		—	%

Schedule of principal components of deferred tax assets

The principal components of the Company's deferred tax assets are as follows (in thousands):

	December 31,

	2011			2012
Deferred tax assets:
Net operating loss carryforwards	$	4,562		$	12,532
Capitalized research and development		148			1,664
Research and development credits		385			508
Stock-based compensation		82			797
Other		20			(23	)

Gross deferred tax assets		5,197			15,478
Valuation allowance		(5,197	)		(15,478	)

Net deferred tax asset	$	—		$	—

Commitments and contingencies (Tables)

12 Months Ended

Dec. 31, 2012

Commitments and contingencies

Schedule of minimum aggregate future lease commitments

The minimum aggregate future lease commitments are as follows (in thousands):


2013		360
2014		307

	$	667

Quarterly Financial Information Quarterly Financial Information (unaudited, in thousands, except per share data) (Tables)

12 Months Ended

Dec. 31, 2012

Quarterly Financial Information (unaudited, in thousands, except per share data)

Schedule of Quarterly Financial Information

Quarterly Financial Information (unaudited, in thousands, except per share data)

	First Quarter Ended March 31, 2012			Second Quarter Ended June 30, 2012			Third Quarter Ended September 30, 2012			Fourth Quarter Ended December 31, 2012

Operating expenses:
Research and development	$	4,803		$	4,683		$	8,132	(b)	$	4,094
General and administrative		2,125			2,213			2,298			3,882

Total operating expenses		6,928			6,896			10,430			7,976

Loss from operations		(6,928	)		(6,896	)		(10,430	)		(7,976	)
Interest income		57			71			63			55

Net loss	$	(6,871	)	$	(6,825	)	$	(10,367	)	$	(7,921	)

Net loss per share applicable to common stockholders-basic and diluted	$	(0.47	)	$	(0.34	)	$	(0.51	)	$	(0.39	)
Weighted average number of common shares used in net loss per share applicable to common stockholders-basic and diluted		14,693	(a)		19,863			20,160			20,309

	First Quarter Ended March 31, 2011			Second Quarter Ended June 30, 2011			Third Quarter Ended September 30, 2011			Fourth Quarter Ended December 31, 2011

Operating expenses:
Research and development	$	675		$	1,726		$	3,082		$	4,400
General and administrative		471			759			965			1,620

Total operating expenses		1,146			2,485			4,047			6,020

Loss from operations		(1,146	)		(2,485	)		(4,047	)		(6,020	)
Interest income		—			—			—			15

Net loss	$	(1,146	)	$	(2,485	)	$	(4,047	)	$	(6,005	)

Net loss per share applicable to common stockholders-basic and diluted	$	(1.06	)	$	(2.03	)	$	(2.98	)	$	(4.01	)
Weighted average number of common shares used in net loss per share applicable to common stockholders-basic and diluted		1,089			1,225			1,361			1,500

(a): In February 2012, the Company completed its initial public offering, which resulted in net proceeds of approximately $56.8 million from the issuance of 6,325,000 shares of common stock, which includes the sale of 825,000 shares under the underwriters' over-allotment option. In connection with the initial public offering, all of the outstanding shares of the Company's redeemable convertible preferred stock were converted into 11,740,794 of common stock.
(b): In the quarter ended September 30, 2012, the Company paid a license fee of $1.5 million in cash and issued 192,012 shares of the Company's common stock, which were valued at $2.0 million on the date of issuance.

Nature of business (Details) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Feb. 28, 2012 USD ($) $ / shares shares	Jan. 31, 2012	Dec. 31, 2012 USD ($) shares	Dec. 31, 2011 USD ($)
Nature of business
Deficit accumulated during the development stage			$ 46,451	$ 14,467
Cash, cash equivalents and investments			91,496	$ 56,806
Initial public offering
Common stock registered sold (in shares) \| shares	6,325,000
Selling price per share (in dollars per share) \| $ / shares	$ 10.00
Net proceeds of IPO	$ 56,800		$ 56,800
Shares of common stock issued upon conversion of redeemable convertible preferred stock \| shares	11,740,794		11,740,794
Reverse Stock Split
Reverse stock spilt conversion ratio for common stock		3.5

Significant accounting policies (Details)	12 Months Ended
Significant accounting policies (Details)	Dec. 31, 2012 USD ($) item	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)
Segment and geographic information
Number of operating segments \| item	1
Number of geographic areas \| item	1
Financial assets
Cash equivalents	$ 10,096,000	$ 20,954,000
Short-term investments	46,480,000	26,857,000
Long-term investments	81,424,000	35,851,000
Financial liabilities
Obligation to issue warrant		406,000
Financial instruments recorded at fair value			$ 0
Total
Financial assets
Cash equivalents	8,171,000	4,102,000
Short-term investments	46,480,000	26,857,000
Long-term investments	34,944,000	8,994,000
Total financial assets	89,595,000	39,953,000
Financial liabilities
Obligation to issue warrant		406,000
Total financial liabilities		406,000
Quoted prices in active markets (Level 1)
Financial assets
Cash equivalents	8,171,000	3,102,000
Total financial assets	8,171,000	3,102,000
Significant other observable inputs (Level 2)
Financial assets
Cash equivalents		1,000,000
Short-term investments	46,480,000	26,857,000
Long-term investments	34,944,000	8,994,000
Total financial assets	$ 81,424,000	36,851,000
Significant unobservable inputs (Level 3)
Financial liabilities
Obligation to issue warrant		406,000
Total financial liabilities		$ 406,000

Significant accounting policies (Details 2) - USD ($)		12 Months Ended
Significant accounting policies (Details 2) - USD ($)	Jan. 26, 2012	Dec. 31, 2012	Dec. 31, 2011
Inputs used to determine the fair value of the obligation to issue the warrant
Obligation to issue warrant			$ 406,000
Significant unobservable inputs (Level 3)
Inputs used to determine the fair value of the obligation to issue the warrant
Obligation to issue warrant			406,000
Poniard Pharmaceuticals Inc.
Disclosure of warrant
Warrant term from the date of issuance		3 years
Number of trading days preceding the issuance of the warrant during which the exercise price of the warrant is equal to the average closing price of common stock		5 days
Inputs used to determine the fair value of the obligation to issue the warrant
Probability of achieving milestone (as a percent)		100.00%
Obligation to issue warrant	$ 837,000		$ 406,000
Increase in fair value of obligation to issue the warrant	$ 431,000
Poniard Pharmaceuticals Inc. \| Significant unobservable inputs (Level 3)
Inputs used to determine the fair value of the obligation to issue the warrant
Exercise price (in dollars per share)	$ 11.09
Estimated stock price contingent upon milestone achievement (in dollars per share)	$ 12.60
Expected term	4 years
Volatility (as a percent)	75.00%
Dividend yield (as a percent)	0.00%
Risk-free rate (as a percent)	0.54%
Probability of achieving milestone (as a percent)	80.00%
Probability of scenario (as a percent)	100.00%
Poniard Pharmaceuticals Inc. \| Significant unobservable inputs (Level 3) \| Non-IPO
Inputs used to determine the fair value of the obligation to issue the warrant
Exercise price (in dollars per share)			$ 6.86
Estimated stock price contingent upon milestone achievement (in dollars per share)			$ 3.22
Expected term			4 years 1 month 6 days
Volatility (as a percent)			70.00%
Dividend yield (as a percent)			0.00%
Risk-free rate (as a percent)			0.60%
Probability of achieving milestone (as a percent)			80.00%
Probability of scenario (as a percent)			20.00%
Poniard Pharmaceuticals Inc. \| Significant unobservable inputs (Level 3) \| IPO
Inputs used to determine the fair value of the obligation to issue the warrant
Exercise price (in dollars per share)			$ 10.00
Estimated stock price contingent upon milestone achievement (in dollars per share)			$ 8.54
Expected term			4 years 1 month 6 days
Volatility (as a percent)			70.00%
Dividend yield (as a percent)			0.00%
Risk-free rate (as a percent)			0.60%
Probability of achieving milestone (as a percent)			80.00%
Probability of scenario (as a percent)			80.00%

Significant accounting policies (Details 3) - USD ($)	12 Months Ended
Significant accounting policies (Details 3) - USD ($)	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012
Significant accounting policies
Charges for other-than-temporary declines in fair value of short-term or long-term investments	$ 0	$ 0
Realized gains or losses on investments	0	0
Investments with a fair value that is significantly lower than the amortized cost basis	0
Investments
Cash and cash equivalents, Amortized Cost	20,954,000	$ 3,584,000	$ 10,096,000
Cash and cash equivalents, Fair Value	20,954,000		10,096,000
Investments, Amortized Cost
Amortized Cost	35,852,000		81,400,000
Investments, Gross Unrealized Gains
Gross Unrealized Gains	6,000		28,000
Investments, Gross Unrealized Losses
Investments, Gross Unrealized Losses	(7,000)		(4,000)
Fair Value
Investments, Fair Value	35,851,000		81,424,000
Total cash, cash equivalents, and investments, Amortized Cost	56,806,000		91,496,000
Total cash, cash equivalents, and investments, Fair Value	56,805,000		91,520,000
Government-sponsored enterprise securities
Investments, Amortized Cost
Due within 1 year	10,900,000		44,480,000
Due within 1 - 2 years	8,998,000		36,920,000
Investments, Gross Unrealized Gains
Due within 1 year	2,000		14,000
Due within 1 - 2 years	1,000		14,000
Investments, Gross Unrealized Losses
Due within 1 year	(1,000)		(3,000)
Due within 1 - 2 years	(5,000)		(1,000)
Fair Value
Due within 1 year	10,901,000		44,491,000
Due within 1 - 2 years	8,994,000		36,933,000
Commercial paper secured by the U.S. government
Investments, Amortized Cost
Due within 1 year	15,954,000
Investments, Gross Unrealized Gains
Due within 1 year	3,000
Investments, Gross Unrealized Losses
Due within 1 year	(1,000)
Fair Value
Due within 1 year	15,956,000
Cash and money market accounts
Investments
Cash and cash equivalents, Amortized Cost	19,954,000		10,096,000
Cash and cash equivalents, Fair Value	19,954,000		$ 10,096,000
Government-sponsored enterprise securities
Investments
Cash and cash equivalents, Amortized Cost	1,000,000
Cash and cash equivalents, Fair Value	$ 1,000,000

Significant accounting policies (Details 4)	12 Months Ended
Significant accounting policies (Details 4)	Dec. 31, 2012 USD ($) item
Concentrations of credit risk and off-balance sheet risk
Number of financial institutions in which cash, cash equivalents and investments were deposited \| item	2
Significant off-balance sheet concentrations of credit risk	0.00%
Property and equipment
Impairment losses on long-lived assets \| $	$ 0
Laboratory equipment
Property and equipment
Estimated useful lives	5 years
Furniture
Property and equipment
Estimated useful lives	5 years
Computer equipment
Property and equipment
Estimated useful lives	3 years

- Definition

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 958
-SubTopic 225
-Section 45
-Paragraph 11
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6743430&loc=d3e92212-112881

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Impairment
-URI http://asc.fasb.org/extlink&oid=6515133

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2420-110228

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2921-110230

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 26
-Subparagraph b
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 144
-Paragraph 7, 25
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Significant accounting policies (Details 5) - shares	5 Months Ended	12 Months Ended		29 Months Ended
Significant accounting policies (Details 5) - shares	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
Net loss per share
Potentially anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	3,328,926	3,070,445	13,580,669	3,070,445
Preferred Stock
Net loss per share
Potentially anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	1,142,857		11,740,794
Outstanding stock options
Net loss per share
Potentially anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	177,143	1,424,241	405,141	1,424,241
Restricted stock units
Net loss per share
Potentially anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)		899,204		899,204
Unvested restricted stock
Net loss per share
Potentially anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	2,008,926	747,000	1,434,734	747,000

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Antidilution
-URI http://asc.fasb.org/extlink&oid=6505113

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Diluted Earnings Per Share
-URI http://asc.fasb.org/extlink&oid=6510752

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Contingent Stock Agreement
-URI http://asc.fasb.org/extlink&oid=6508534

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 40
-Subparagraph c
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 13, 14
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 07-4
-Paragraph 4
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 128
-Paragraph 171
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Property and equipment (Details) - USD ($)	5 Months Ended	12 Months Ended		29 Months Ended
Property and equipment (Details) - USD ($)	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
Property and equipment
Property and equipment, gross		$ 1,088,000	$ 792,000	$ 1,088,000
Less: accumulated depreciation		(277,000)	(83,000)	(277,000)
Property and equipment, net		811,000	709,000	811,000
Depreciation expenses	$ 0	207,000	83,000	290,000
Laboratory equipment
Property and equipment
Property and equipment, gross		1,017,000	721,000	1,017,000
Computer equipment
Property and equipment
Property and equipment, gross		27,000	27,000	27,000
Furniture
Property and equipment
Property and equipment, gross		$ 44,000	$ 44,000	$ 44,000

- Definition

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

+ References + Details

Prepaid expenses and other current assets (Details) - USD ($) $ in Thousands	Dec. 31, 2012	Dec. 31, 2011
Prepaid expenses and other current assets
Prepaid contract research organization costs	$ 274
Interest receivable	161	$ 53
Prepaid other	71	77
Prepaid expenses and other current assets	$ 506	$ 130

Accrued expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2012	Dec. 31, 2011
Accrued expenses
Professional fees	$ 183	$ 520
Compensation and related benefits	173	86
Contract research organization costs	69	217
Consulting	36
Deferred rent	36	27
Other	54	23
Accrued expenses	$ 551	$ 873

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable for professional fees, such as for legal and accounting services received. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References + Details

- Definition

For a classified balance sheet, the cumulative difference as of the balance sheet date between the payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense, by the lessor or lessee, respectively, within one year of the balance sheet date.

+ References + Details

- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable arising from transactions not otherwise specified in the taxonomy. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References + Details

Redeemable convertible preferred stock (Details)		1 Months Ended			5 Months Ended	12 Months Ended		29 Months Ended
Redeemable convertible preferred stock (Details)	Feb. 02, 2012 shares	Nov. 30, 2011 USD ($) $ / shares shares	Jul. 31, 2011 USD ($) $ / shares shares	Nov. 30, 2010 USD ($) $ / shares shares	Dec. 31, 2010 USD ($)	Dec. 31, 2012 USD ($) item $ / shares shares	Dec. 31, 2011 USD ($) $ / shares shares	Dec. 31, 2012 USD ($) item $ / shares shares	Feb. 28, 2012 $ / shares	Apr. 30, 2011 $ / shares
Redeemable convertible preferred stock
Redeemable convertible preferred stock							$ 68,141,000
Selling price per share (in dollars per share) \| $ / shares									$ 10.00
Gross proceeds from sale of shares					$ 3,921,000		64,186,000	$ 68,107,000
Embedded derivatives that would require bifurcation \| item						0		0
Intrinsic value of common stock into which the Preferred Stock is convertible						$ 0		$ 0
Conversion
Conversion ratio						1
Conversion price after reduction required for automatic conversion of preferred stock (in dollars per share) \| $ / shares						$ 8.75
Liquidation preference
Aggregate amount payable to preferred stockholders as number of times of applicable Original Purchase Price						1.75
Voting rights
Number of votes for each equivalent common share into which the Preferred Stock is convertible \| item						1
Voting rights percentage additionally required for certain events						60.00%
Number of directors whom preferred and common stockholders voting as one class are entitled to elect \| item						2
Number of directors whom common stockholders are entitled to elect \| item						1
Redemption
Number of installments in which redemption is payable \| item						3
Minimum
Conversion
Common stock issuance price required for automatic conversion of preferred stock (in dollars per share) \| $ / shares						$ 10.50
Proceeds from common stock issuance required for automatic conversion of preferred stock						$ 35,000,000
Percentage of preferred stockholders' consent required for automatic conversion						60.00%
Liquidation preference
Percentage of preferred stockholders required for election of not granting liquidation preference						60.00%
Voting rights
Amount of indebtedness in case of issuance of any debt security allowed without any voting rights						$ 1,000,000
Convertible Preferred Stock
Redeemable convertible preferred stock
Shares of common stock issued upon conversion of redeemable convertible preferred stock \| shares	11,740,794
Series A Preferred Stock and Series B Preferred Stock
Voting rights
Voting rights percentage required for certain events						60.00%
Series A redeemable convertible preferred stock
Redeemable convertible preferred stock
Redeemable convertible preferred stock							$ 15,939,000
Par value (in dollars per share) \| $ / shares							$ 0.0001
Shares authorized \| shares						0	16,000	0
Shares issued \| shares						0	16,000	0
Shares outstanding \| shares						0	16,000	0
Liquidation preference							$ 16,000,000
Shares sold \| shares				4,000,000
Selling price per share (in dollars per share) \| $ / shares				$ 1.00						$ 1.00
Gross proceeds from sale of shares				$ 4,000,000
Issuance costs				$ 79,000
Additional issuance costs incurred as part of the second closing						$ 0
Liquidation preference
Liquidation preference per share (in dollars per share) \| $ / shares						$ 1.00		$ 1.00
Voting rights
Number of directors whom preferred stockholders are entitled to elect \| item						4
Series A redeemable convertible preferred stock \| Minimum
Redemption
Redeemable portion						0.67
Series B redeemable convertible preferred stock
Redeemable convertible preferred stock
Redeemable convertible preferred stock							$ 31,948,000
Par value (in dollars per share) \| $ / shares							$ 0.0001
Shares authorized \| shares						0	16,025	0
Shares issued \| shares						0	16,025	0
Shares outstanding \| shares						0	16,025	0
Liquidation preference							$ 32,050,000
Shares sold \| shares			16,000,000
Selling price per share (in dollars per share) \| $ / shares			$ 2.00
Gross proceeds from sale of shares			$ 32,000,000
Issuance costs			$ 113,000
Liquidation preference
Liquidation preference per share (in dollars per share) \| $ / shares						$ 2.00		$ 2.00
Series B redeemable convertible preferred stock \| Minimum
Redemption
Redeemable portion						0.67
Series C redeemable convertible preferred stock
Redeemable convertible preferred stock
Redeemable convertible preferred stock							$ 20,254,000
Par value (in dollars per share) \| $ / shares							$ 0.0001
Shares authorized \| shares						0	9,068	0
Shares issued \| shares						0	9,068	0
Shares outstanding \| shares						0	9,068	0
Liquidation preference							$ 20,403,000
Shares sold \| shares		9,100,000
Selling price per share (in dollars per share) \| $ / shares		$ 2.25
Gross proceeds from sale of shares		$ 20,400,000
Issuance costs		$ 153,000
Liquidation preference
Liquidation preference per share (in dollars per share) \| $ / shares						$ 2.25		$ 2.25

Common stock (Details) shares in Thousands	12 Months Ended
Common stock (Details) shares in Thousands	Dec. 31, 2012 item shares	Dec. 31, 2011 shares
Common stock
Shares of common stock reserved for potential conversion	3,930	12,304
Number of votes available for each share of common stock \| item	1
Equity compensation plans
Common stock
Shares of common stock reserved for potential conversion	3,930	563
Series A Preferred Stock
Common stock
Shares of common stock reserved for potential conversion		4,571
Series B Preferred Stock
Common stock
Shares of common stock reserved for potential conversion		4,579
Series C Preferred Stock
Common stock
Shares of common stock reserved for potential conversion		2,591

Stock-based compensation (Details) $ in Thousands	5 Months Ended	12 Months Ended		29 Months Ended
Stock-based compensation (Details) $ in Thousands	Dec. 31, 2010 USD ($)	Dec. 31, 2012 USD ($) item	Dec. 31, 2011 USD ($)	Dec. 31, 2012 USD ($)
Stock-based compensation
Total stock-based compensation expense	$ 52	$ 7,400	$ 1,635	$ 9,087
Number of equity compensation plans \| item		2
Vesting percentage in one year from vesting start date		25.00%
Vesting period for twenty five percent from grant date		1 year
Vesting percentage in equal quarterly installment		75.00%
Vesting period for seventy-five vesting percentage		3 years
Expiration term		10 years
Research and development
Stock-based compensation
Total stock-based compensation expense	24	$ 2,956	981	3,961
General and administrative
Stock-based compensation
Total stock-based compensation expense	$ 28	$ 4,444	$ 654	$ 5,126

Stock-based compensation (Details2) - USD ($)	1 Months Ended		5 Months Ended	12 Months Ended		29 Months Ended
Stock-based compensation (Details2) - USD ($)	Feb. 28, 2012	Nov. 30, 2011	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Mar. 31, 2011
Stock-based compensation
Vesting percentage in equal quarterly installment				75.00%
Vesting period for seventy-five vesting percentage				3 years
Stock-based compensation expense			$ 52,000	$ 7,400,000	$ 1,635,000	$ 9,087,000
Stock options
Stock-based compensation
Shares granted				1,039,714
Shares forfeited				15,219
Options exercised (in shares)				(5,395)
Stock-based compensation expense				$ 1,600,000	19,000	1,600,000
Additional disclosures
Total unrecognized stock-based compensation expense (in dollars)				$ 5,400,000		5,400,000
Weighted-average recognition period				3 years
Restricted common stock
Stock-based compensation
Stock-based compensation expense			$ 51,000	$ 3,300,000	$ 1,400,000	$ 4,800,000
Shares
Unvested at the beginning of the period (in shares)				1,434,734
Vested (in shares)				(542,421)
Forfeited (in shares)				(145,313)
Unvested at the end of the period (in shares)				747,000	1,434,734	747,000
Weighted-average grant date fair value
Unvested at the beginning of the period (in dollars per share)				$ 0.02530
Granted (in dollars per shares)			$ 0.00035		$ 0.28	$ 0.02
Vested (in dollars per shares)				0.02920
Cancelled (in dollars per shares)				0.00035
Unvested at the end of the period (in dollars per share)				$ 0.02730	$ 0.02530	$ 0.02730
Additional disclosures
Total unrecognized stock-based compensation expense (in dollars)				$ 4,200,000		$ 4,200,000
Weighted-average recognition period				1 year 9 months
Restricted common stock \| Founders
Stock-based compensation
Shares issued				2,857,138
Vesting percentage				25.00%
Vesting percentage in equal quarterly installment				75.00%
Vesting period for seventy-five vesting percentage				4 years
RSUs
Stock-based compensation
Shares issued				103,306
Vesting percentage				25.00%
Stock-based compensation expense				$ 126,000
Shares
Granted (in shares)				909,918
Vested (in shares)				(77,479)
Forfeited (in shares)				(10,714)
Unvested at the end of the period (in shares)				899,204		899,204
Weighted-average grant date fair value
Granted (in dollars per shares)				$ 10.62
Vested (in dollars per shares)				9.68
Cancelled (in dollars per shares)				11.10
Unvested at the end of the period (in dollars per share)				$ 10.70		$ 10.70
Additional disclosures
Total unrecognized stock-based compensation expense (in dollars)				$ 6,500,000		$ 6,500,000
Weighted-average recognition period				3 years
2012 Plan
Stock-based compensation
Number of shares reserved	3,428,571
Additional number of shares reserved from shares available for future grant under the 2010 plan	30,101
Annual increase in number of shares reserved				1,285,714
Percentage of outstanding shares of common stock used to compute annual increase in number of shares reserved				4.00%
2012 Plan \| Stock options
Stock-based compensation
Shares granted				1,039,714
Shares forfeited				8,328
2012 Plan \| Restricted common stock
Shares
Granted (in shares)				909,918
Forfeited (in shares)				(10,714)
2010 Plan
Stock-based compensation
Number of shares reserved							571,242
Initial number of shares reserved		404,762
Shares available for future grants	30,101
2010 Plan \| Stock options
Stock-based compensation
Shares granted				405,141
Options exercised (in shares)				(5,395)
Shares forfeited and repurchased				(126,891)
2010 Plan \| Restricted common stock
Shares
Granted (in shares)				256,000

Stock-based compensation (Details 3) - USD ($)	5 Months Ended	12 Months Ended		29 Months Ended
Stock-based compensation (Details 3) - USD ($)	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
Additional disclosures
Stock-based compensation expense	$ 52,000	$ 7,400,000	$ 1,635,000	$ 9,087,000
Stock options
Shares
Outstanding at the beginning of the period (in shares)		405,141
Granted (in shares)		1,039,714
Exercised (in shares)		(5,395)
Cancelled (in shares)		(15,219)
Outstanding at the end of the period (in shares)		1,424,241	405,141	1,424,241
Vested at the end of the period (in shares)		384,712		384,712
Vested and expected to vest at end of period (in shares)		1,382,496		1,382,496
Weighted-average price per share
Outstanding at the beginning of the period (in dollars per share)		$ 0.75
Granted (in dollars per share)		9.25
Exercised (in dollars per share)		0.56
Cancelled (in dollars per share)		6.50
Outstanding at the end of the period (in dollars per share)		6.90	$ 0.75	$ 6.90
Vested at the end of the period (in dollars per share)		6.00		6.00
Vested and expected to vest at end of the period (in dollars per share)		$ 6.87		$ 6.87
Weighted-average remaining contractual term
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2		9 years 3 months 18 days
Vested at the end of the period		9 years
Vested and expected to vest at the end of the period		9 years 3 months 18 days
Aggregate intrinsic value
Outstanding at the end of the period (in dollars)		$ 3,451,000		$ 3,451,000
Vested at the end of the period (in dollars)		1,343,000		1,343,000
Vested and expected to vest at end of the period (in dollars)		$ 3,415,000		3,415,000
Assumptions used to estimate fair value of each stock-based award on the grant date
Risk-free interest rate (as a percent)	2.00%
Risk-free interest rate, minimum (as a percent)		0.80%	1.10%
Risk-free interest rate, maximum (as a percent)		1.70%	2.70%
Volatility (as a percent)	67.00%
Volatility, minimum (as a percent)		70.00%	69.00%
Volatility, maximum (as a percent)		77.00%	70.00%
Expected term	6 years 1 month 6 days		6 years 3 months
Additional disclosures
Stock-based compensation expense		$ 1,600,000	$ 19,000	$ 1,600,000
Weighted-average grant date fair value (in dollars per share)	$ 0.18	$ 6.03	$ 0.75	$ 4.48
Total unrecognized stock-based compensation expense (in dollars)		$ 5,400,000		$ 5,400,000
Weighted-average recognition period		3 years
Stock options \| Minimum
Assumptions used to estimate fair value of each stock-based award on the grant date
Expected term		5 years 3 months 18 days
Stock options \| Maximum
Assumptions used to estimate fair value of each stock-based award on the grant date
Expected term		6 years 1 month 6 days

Income taxes (Details) $ in Millions	Dec. 31, 2012 USD ($)
Federal
Operating loss carryforwards
Net operating loss carryforwards	$ 31.9
State
Operating loss carryforwards
Net operating loss carryforwards	$ 31.9

Income taxes (Details 2)	12 Months Ended
Income taxes (Details 2)	Dec. 31, 2012 USD ($)
Tax credit carryforwards
Testing period for changes in ownership interest of significant shareholders	3 years
Federal
Tax credit carryforwards
Tax credits	$ 358,000
State
Tax credit carryforwards
Tax credits	$ 229,000

Income taxes (Details 3) - USD ($)	5 Months Ended	12 Months Ended
Income taxes (Details 3) - USD ($)	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of income taxes computed using the U.S. federal statutory rate
Income tax benefit using U.S. federal statutory rate (as a percent)		34.00%	34.00%
State income taxes, net of federal benefit (as a percent)		4.61%	4.78%
Research and development tax credits (as a percent)			1.65%
Permanent items (as a percent)		(5.96%)	(4.78%)
Change in the valuation allowance (as a percent)		(32.19%)	(35.65%)
Other (as a percent)		(0.46%)
Effective income tax rate (as a percent)		0.00%
Deferred tax assets:
Net operating loss carryforwards		$ 12,532,000	$ 4,562,000
Capitalized research and development		1,664,000	148,000
Research and development credits		508,000	385,000
Stock-based compensation		797,000	82,000
Other		(23,000)	20,000
Gross deferred tax assets		15,478,000	5,197,000
Valuation allowance		(15,478,000)	(5,197,000)
Net deferred tax asset		0
Increase in valuation allowance	$ 10,300,000	320,000	$ 4,900,000
Adjustment for unrecognized income tax benefits		0
Unrecognized tax benefits		0
Interest and penalties accrued related to unrecognized tax benefits		0
Uncertain tax positions		$ 0

Commitments and contingencies (Details) - USD ($)	1 Months Ended	5 Months Ended	12 Months Ended		29 Months Ended
Commitments and contingencies (Details) - USD ($)	May 31, 2011	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
Commitments and contingencies
Rent paid to the shareholder		$ 12,000	$ 0	$ 34,000
Rent free period	4 months
Extension period of lease term			2 years
Letter of credit secured in connection with the lease, included in restricted cash			$ 86,000	86,000	$ 86,000
Minimum aggregate future lease commitments
2013			360,000		360,000
2014			307,000		307,000
Minimum future lease commitments			667,000		667,000
Rent expense		$ 12,000	$ 323,000	$ 251,000	$ 786,000

License agreements (Details) - USD ($)					1 Months Ended	3 Months Ended	5 Months Ended	12 Months Ended	29 Months Ended
License agreements (Details) - USD ($)	Jul. 11, 2012	May 11, 2012	Dec. 16, 2011	Nov. 17, 2011	Oct. 31, 2010	Sep. 30, 2012	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2012
License agreements
Common stock issued (in shares)						192,012
Fair value of the shares of common stock (in dollars per share)								$ 0.28
Fair value of the shares of common stock issued recorded as research and development expense							$ 46,000	$ 1,957,000	$ 2,003,000
One-time cash payment						$ 1,500,000
Exclusive license agreement \| The Licensor
License agreements
Upfront license fee paid and patent related fees and costs incurred by the Licensor and affiliates reimbursed by the Company					$ 104,000
Common stock issued (in shares)					166,664
Fair value of the shares of common stock (in dollars per share)					$ 0.28
Fair value of the shares of common stock issued recorded as research and development expense					$ 46,000
Number of days' prior written notice required to terminate the agreement					90 days
Exclusive license agreement \| The Licensor \| Maximum
License agreements
Milestone payments upon the achievement of specified development, regulatory and commercialization milestones					$ 1,600,000
Exclusive license agreement \| Poniard Pharmaceuticals Inc.
License agreements
Number of days' prior written notice required to terminate the agreement				90 days
Milestone payments upon the achievement of specified development and regulatory milestones				$ 13,300,000
Number of shares of common stock in the warrant issued upon the first dosing of the first patient in a Phase 1 clinical trial of a licensed product (in shares)				142,857
Number of trading days preceding the issuance of the warrant during which the exercise price of the warrant is equal to the average closing price of common stock				5 days
Exclusive license agreement \| Pfizer
License agreements
Common stock issued (in shares)	192,012
Fair value of the shares of common stock issued recorded as research and development expense								$ 2,000,000
One-time cash payment	$ 1,500,000
Royalty obligations term	10 years
Exclusive license agreement \| Pfizer \| Maximum
License agreements
Eligible amount receivable on developmental milestones by Pfizer	$ 2,000,000
Additional payable on successful attainment of regulatory and commercial sales milestones	$ 125,000,000
Amendment and restatement of an existing non-exclusive license agreement \| The Licensor \| Maximum
License agreements
Milestone payments triggered upon the achievement of specified regulatory and commercialization milestones			$ 825,000
Dual inhibitors of PI3K and mTOR, including related patent right agreement \| S*Bio Pte Ltd
License agreements
Upfront license fee paid and patent related fees and costs incurred by the Licensor and affiliates reimbursed by the Company		$ 350,000
Dual inhibitors of PI3K and mTOR, including related patent right agreement \| S*Bio Pte Ltd \| Maximum
License agreements
Milestone payments upon the achievement of specified development and regulatory milestones		$ 21,000,000
Deduction in royalty payments as percentage of amount paid to third party								50.00%

Employee benefit plan (Details) - USD ($)	5 Months Ended	12 Months Ended		29 Months Ended
Employee benefit plan (Details) - USD ($)	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
Employee benefit plan
Contributions made under 401(k) plan	$ 0	$ 116,000	$ 46,000	$ 162,000

Quarterly Financial Information Quarterly Financial Information (unaudited, in thousands, except per share data) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended								5 Months Ended	12 Months Ended		29 Months Ended
	Feb. 28, 2012	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012
Operating expenses:
Research and development		$ 4,094	$ 8,132	$ 4,683	$ 4,803	$ 4,400	$ 3,082	$ 1,726	$ 675	$ 400	$ 21,712	$ 9,883	$ 31,995
General and administrative		3,882	2,298	2,213	2,125	1,620	965	759	471	384	10,518	3,815	14,717
Total operating expenses		7,976	10,430	6,896	6,928	6,020	4,047	2,485	1,146	784	32,230	13,698	46,712
Loss from operations		(7,976)	(10,430)	(6,896)	(6,928)	(6,020)	(4,047)	(2,485)	(1,146)	(784)	(32,230)	(13,698)	(46,712)
Interest income		55	63	71	57	15					246	15	261
Net loss		$ (7,921)	$ (10,367)	$ (6,825)	$ (6,871)	$ (6,005)	$ (4,047)	$ (2,485)	$ (1,146)	$ (784)	$ (31,984)	$ (13,683)	$ (46,451)
Net loss per share applicable to common stockholders-basic and diluted (in dollars per share)		$ (0.39)	$ (0.51)	$ (0.34)	$ (0.47)	$ (4.01)	$ (2.98)	$ (2.03)	$ (1.06)	$ (0.91)	$ (1.70)	$ (10.59)	$ (5.44)
Weighted-average number of common shares used in net loss per share applicable to common stockholders-basic and diluted		20,309,000	20,160,000	19,863,000	14,693,000	1,500,000	1,361,000	1,225,000	1,089,000	850,000	18,765,000	1,295,000	8,547,000
Net proceeds from shares of common stock issued in initial public offering	$ 56,800										$ 56,800
Number of shares of common stock issued in initial public offering	6,325,000
Shares of common stock sold under underwriters' over-allotment option	825,000
Shares of common stock issued upon conversion of redeemable convertible preferred stock	11,740,794
License fee paid in cash			$ 1,500
Common stock issued (in shares)			192,012
Value of common stock issued			$ 2,000

Label	Element	Value
Stock Issued During Period Value in Exchange for License	vstm_StockIssuedDuringPeriodValueInExchangeForLicense	$ 46,000
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	52,000
Stock Issued During Period, Value, Issued for Services	us-gaap_StockIssuedDuringPeriodValueIssuedForServices	$ 1,000
Common Stock [Member]
Stock Issued During Period, Shares, Issued for Services	us-gaap_StockIssuedDuringPeriodSharesIssuedForServices	714,286
Stock Issued During Period, Shares, Restricted Stock Award, Gross	us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardGross	133,926
Stock Issued During Period Shares in Exchange for License	vstm_StockIssuedDuringPeriodSharesInExchangeForLicense	166,664
Stock Issued During Period, Value, Issued for Services	us-gaap_StockIssuedDuringPeriodValueIssuedForServices	$ 1,000
Additional Paid-in Capital [Member]
Stock Issued During Period Value in Exchange for License	vstm_StockIssuedDuringPeriodValueInExchangeForLicense	46,000
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition	us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	52,000
Temporary Equity, Accretion to Redemption Value, Adjustment	us-gaap_TemporaryEquityAccretionToRedemptionValueAdjustment	2,000
Redeemable Convertible Preferred Stock [Member]
Temporary Equity, Accretion to Redemption Value, Adjustment	us-gaap_TemporaryEquityAccretionToRedemptionValueAdjustment	(2,000)
Retained Earnings [Member]
Net Income (Loss) Attributable to Parent	us-gaap_NetIncomeLoss	(784,000)
Redeemable Convertible Preferred Stock Series A [Member] \| Redeemable Convertible Preferred Stock [Member]
Temporary Equity, Stock Issued During Period, Value, New Issues	us-gaap_TemporaryEquityStockIssuedDuringPeriodValueNewIssues	$ 3,921,000
Temporary Equity Stock Issued During Period Shares New Issues	vstm_TemporaryEquityStockIssuedDuringPeriodSharesNewIssues	4,000,000