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Document and Entity Information - shares	6 Months Ended
Document and Entity Information - shares	Jun. 30, 2014	Jul. 31, 2014
Document and Entity Information
Entity Registrant Name	Verastem, Inc.
Entity Central Index Key	0001526119
Document Type	10-Q
Document Period End Date	Jun. 30, 2014
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		25,842,328
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q2

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 22,391	$ 18,889
Short-term investments	76,204	82,423
Restricted cash	86	86
Prepaid expenses and other current assets	877	557
Total current assets	99,558	101,955
Property and equipment, net	1,489	631
Long-term investments	5,757	22,344
Restricted cash	203
Other assets	335	331
Total assets	107,342	125,261
Current liabilities:
Accounts payable	3,159	2,760
Accrued expenses	4,165	4,327
Liability classified stock-based compensation awards	547	717
Total current liabilities	7,871	7,804
Other liabilities	292	11
Stockholders' equity:
Convertible preferred stock, $0.0001 par value; 5,000 shares authorized; none issued and outstanding
Common stock, $0.0001 par value; 100,000 shares authorized; 25,722 and 25,328 shares issued and outstanding at June 30, 2014 and December 31, 2013, respectively	3	3
Additional paid-in capital	212,883	205,068
Accumulated other comprehensive income	29	28
Accumulated deficit	(113,736)	(87,653)
Total stockholders' equity	99,179	117,446
Total liabilities and stockholders' equity	$ 107,342	$ 125,261

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares shares in Thousands	Jun. 30, 2014	Dec. 31, 2013
CONDENSED CONSOLIDATED BALANCE SHEETS
Convertible preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Convertible preferred stock, shares authorized	5,000	5,000
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	100,000
Common stock, shares issued	25,722	25,328
Common stock, shares outstanding	25,722	25,328

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating expenses:
Research and development	$ 8,305	$ 6,045	$ 16,716	$ 11,341
General and administrative	4,782	4,239	9,505	8,024
Total operating expenses	13,087	10,284	26,221	19,365
Loss from operations	(13,087)	(10,284)	(26,221)	(19,365)
Interest income	65	34	137	78
Net loss	$ (13,022)	$ (10,250)	$ (26,084)	$ (19,287)
Net loss per share-basic and diluted (in dollars per share)	$ (0.51)	$ (0.49)	$ (1.02)	$ (0.94)
Weighted-average number of common shares used in net loss per share-basic and diluted (in shares)	25,669	20,729	25,574	20,607
Comprehensive loss	$ (13,015)	$ (10,271)	$ (26,083)	$ (19,312)

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating activities
Net loss	$ (26,084)	$ (19,287)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	141	112
Amortization of premiums and discounts on available for sale marketable securities	152
Stock-based compensation expense	6,910	5,182
Common Stock issued to purchase technology rights	1,197
Changes in operating assets and liabilities:
Prepaid expenses, other current assets and other assets	(324)	(630)
Accounts payable	(187)	186
Accrued expenses and other liabilities	373	1,781
Liability classified stock-based compensation award	(170)
Net cash used in operating activities	(17,992)	(12,656)
Investing activities
Purchases of property and equipment	(412)	(31)
Purchases of investments	(26,640)	(44,209)
Maturities of investments	49,295	61,479
Increase in restricted cash	(203)
Net cash provided by investing activities	22,040	17,239
Financing activities
Proceeds from the exercise of stock options	11	30
Cash used to settle restricted stock liability awards	(557)	(829)
Net cash used in financing activities	(546)	(799)
Increase in cash and cash equivalents	3,502	3,784
Cash and cash equivalents at beginning of period	18,889	10,096
Cash and cash equivalents at end of period	$ 22,391	$ 13,880

Summary of significant accounting policies	6 Months Ended
Summary of significant accounting policies	Jun. 30, 2014
Summary of significant accounting policies
Summary of significant accounting policies	1. Summary of significant accounting policies Basis of presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States ("GAAP") for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (including those which are normal and recurring) considered necessary for a fair presentation of the interim financial information have been included. When preparing financial statements in conformity with GAAP, the Company must make estimates and assumptions that affect the reported amounts and related disclosures at the date of the financial statements. Actual results could differ from those estimates. Additionally, operating results for the three and six months ended June 30, 2014 are not necessarily indicative of the results that may be expected for any other interim period or for the fiscal year ending December 31, 2014. For further information, refer to the financial statements and footnotes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2013 as filed with the Securities and Exchange Commission ("SEC") on March 6, 2014. Recent Accounting Pronouncements On June 10, 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-10, which simplifies financial reporting for development stage entities by eliminating requirements specific to development stage entities. As a result, entities in a development stage will no longer need to present inception-to-date information about income statement line items, cash flows, and equity transactions. Instead, the new guidance clarifies how these entities should tailor existing disclosures to explain the risks and uncertainties related to their activities. This update is effective for annual periods beginning after December 15, 2014, and early application is permitted for any annual or interim period for which the entity's financial statements have not yet been issued. The Company adopted this guidance prior to issuing the financial statements in this Q2 2014 Form 10-Q. The adoption of ASU 2014-10 impacted disclosure only and did not have any impact on financial position or results of operations. There have been no changes to the Company's significant accounting policies included in the Company's Annual Report on Form 10-K for the year ended December 31, 2013 as filed with the Securities and Exchange Commission on March 6, 2014.

Fair value of financial instruments

6 Months Ended

Jun. 30, 2014

Fair value of financial instruments

Fair value of financial instruments

2. 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 is now established that 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 and liabilities that have been measured at fair value at June 30, 2014 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	$	20,732	$	14,732	$	6,000	$	—
Short-term investments		76,204		—		76,204		—
Long-term investments		5,757		—		5,757		—


Total financial assets	$	102,693	$	14,732	$	87,961	$	—




Financial liabilities
Liability classified stock-based compensation awards	$	547	$	547	$	—	$	—


Total financial liabilities	$	547	$	547	$	—	$	—

The following table presents information about the Company's financial assets and liabilities that have been measured at fair value at December 31, 2013 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	$	17,000	$	17,000	$	—	$	—
Short-term investments		82,423		—		82,423		—
Long-term investments		22,344		—		22,344		—


Total financial assets	$	121,767	$	17,000	$	104,767	$	—




Financial liabilities
Liability classified stock-based compensation awards	$	717	$	717	$	—	$	—


Total financial liabilities	$	717	$	717	$	—	$	—

The Company's cash equivalents and investments are comprised of money market accounts, government-sponsored enterprise securities, corporate bonds and commercial paper of publicly traded companies. These investments have been initially valued at the transaction price and subsequently valued, at the end of each reporting period, utilizing third party pricing services or other market observable data. The pricing services utilize industry standard valuation models, including both income and market based approaches and observable market inputs to determine value. These observable market inputs include reportable trades, benchmark yields, credit spreads, broker/dealer quotes, bids, offers, current spot rates and other industry and economic events. The Company validates the prices provided by third party pricing services by reviewing their pricing methods and matrices, obtaining market values from other pricing sources, analyzing pricing data in certain instances and confirming that the relevant markets are active. After completing its validation procedures, the Company did not adjust or override any fair value measurements provided by the pricing services as of June 30, 2014.

The Company's liability classified stock-based compensation awards are comprised of restricted stock units (RSUs) that allow for greater than minimum statutory tax withholdings. These awards are valued based on the fair value of the Company's common stock underlying the awards, which is traded on an active market. During the first quarter of 2013, the Company amended the terms of certain RSUs to allow for cash tax withholdings greater than the minimum required statutory withholding amount. As a result of this change in the terms of the awards, the outstanding RSUs are considered to be liability instruments. As a result of this modification, the Company records a liability for the fair value of the awards as of each reporting date with the change in fair value recorded through the statement of operations. The Company will record stock-based compensation expense equal to the greater of the original grant date fair value of the awards or the settlement date fair value. During the three and the six months ended June 30, 2014, the Company paid approximately $58,000 and approximately $557,000, respectively, to settle the tax liability for awards that settled during the periods.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Investments

6 Months Ended

Jun. 30, 2014

Investments

Investments

3. Investments

The Company's investments 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) income, until such gains and losses are realized. 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 charges taken for other-than-temporary declines in fair value of short-term or long-term investments during the three and six months ended June 30, 2014 and 2013. The Company recorded approximate unrealized gains and losses of $7,000, $1,000, $(21,000) and $(25,000) during the three and six months ended June 30, 2014 and 2013, respectively. Realized gains and losses are included in interest income in the statement of operations. There were no realized gains or losses recognized during the three and six months ended June 30, 2014 or 2013. The Company utilizes the specific identification method as a basis to determine the cost of securities sold.

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 June 30, 2014, 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.

Cash, cash equivalents and investments at June 30, 2014 and December 31, 2013 consist of the following (in thousands):

	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value

June 30, 2014
Cash and cash equivalents:
Cash and money market accounts	$	16,391	$	—	$	—		$	16,391
Corporate commercial paper		6,000		—		—			6,000


Total cash and cash equivalents	$	22,391	$	—	$	—		$	22,391


Investments:
Government-sponsored enterprise securities (due within 1 year)	$	20,219	$	8	$	—		$	20,227
Corporate bonds (due within 1 year)		55,955		25		(3	)		55,977
Corporate bonds (due within 1 - 2 years)		5,758		—		(1	)		5,757


Total investments	$	81,932	$	33	$	(4	)	$	81,961


Total cash, cash equivalents, and investments	$	104,323	$	33	$	(4	)	$	104,352

	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value

December 31, 2013
Cash and cash equivalents:
Cash and money market accounts	$	18,889	$	—	$	—		$	18,889


Total cash and cash equivalents	$	18,889	$	—	$	—		$	18,889


Investments:
Government-sponsored enterprise securities (due within 1 year)	$	30,652	$	12	$	—		$	30,664
Government-sponsored enterprise securities (due within 1 - 2 years)		4,001		2		—			4,003
Corporate bonds (due within 1 year)		51,735		30		(6	)		51,759
Corporate bonds (due within 1 - 2 years)		18,351		2		(12	)		18,341


Total investments	$	104,739	$	46	$	(18	)	$	104,767


Total cash, cash equivalents, and investments	$	123,628	$	46	$	(18	)	$	123,656

- Definition

The entire disclosure for investments in certain debt and equity securities.

+ References + Details

Accrued expenses

6 Months Ended

Jun. 30, 2014

Accrued expenses

Accrued expenses

4. Accrued expenses

Accrued expenses consist of the following (in thousands):

	June 30, 2014		December 31, 2013

Contract research organization costs	$	2,609	$	1,918
Compensation and related benefits		969		1,687
Professional fees		275		237
License milestones		110		360
Deferred rent		72		38
Other		130		87


	$	4,165	$	4,327

Net loss per share

6 Months Ended

Jun. 30, 2014

Net loss per share

Net loss per share

5. Net loss per share

Basic and diluted net loss per common share is calculated by dividing net loss 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 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. All potentially dilutive securities were excluded from the calculation of diluted net loss per share as the securities were anti-dilutive for all periods presented. The following potentially dilutive securities were excluded from the calculation of diluted net loss per share due to their anti-dilutive effect:

	Three months ended				Six months ended

	June 30, 2014		June 30, 2013		June 30, 2014		June 30, 2013
Outstanding stock options		4,151		2,263		4,151		2,263
Unvested restricted stock		120		538		120		538
Unvested restricted stock units		394		623		394		623

Stock-based compensation

6 Months Ended

Jun. 30, 2014

Stock-based compensation

Stock-based compensation

6. Stock-based compensation

In December 2011, the Company adopted the 2012 Incentive Plan (the 2012 Plan). The 2012 Plan became effective upon the closing of the Company's IPO in February 2012. The 2012 Plan provides for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based and cash awards. Upon effectiveness, the number of shares of common stock that are reserved under the 2012 Plan is the sum of 3,428,571 shares plus the number of shares available under the Company's prior 2010 Plan. The number of shares reserved under the 2012 Plan is increased by the number of shares of common stock (up to a maximum of 571,242 shares) subject to outstanding awards under the 2010 Plan that expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased. 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. On January 1, 2013 and 2014, the shares available under the 2012 Plan increased by 844,448 and 1,026,309 shares of common stock, respectively.

Restricted common stock

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

			Weighted- average purchase price per share

Unvested at December 31, 2013	329,282		$	0.034
Vested	(208,860	)		0.022


Unvested at June 30, 2014	120,422		$	0.056

No restricted common stock was granted during the three and six months ended June 30, 2014 and 2013. The total fair value of shares vested during the three and six months ended June 30, 2014 and 2013 was an approximate $556,000, $1.6 million, an approximate $706,000 and $1.5 million, respectively. As of June 30, 2014, there was an approximate $296,000 of total unrecognized stock-based compensation expense related to unvested restricted common stock. The Company expects to recognize this expense over a remaining weighted average period of 0.3 years.

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

			Weighted- average grant date fair value

Outstanding at December 31, 2013	529,850		$	10.78
Settled	(131,798	)		10.35
Forfeited	(4,284	)		11.00


Outstanding at June 30, 2014	393,768		$	10.92

No RSUs were granted during the three and six months ended June 30, 2014 and 2013. The total fair value of RSUs vested during the three and six months ended June 30, 2014 and 2013 was an approximate $125,000, $1.4 million, an approximate $122,000 and $2.3 million, respectively. As of June 30, 2014, there was $3.1 million of total unrecognized stock-based compensation expense related to unvested RSUs granted under the 2012 Plan. The Company expects to recognize this expense over a weighted average period of 1.6 years.

During the first quarter of 2013, the Company amended the terms of certain RSUs related to a total of 657,058 shares of common stock to allow for tax withholdings greater than the minimum required statutory withholding amount, of which 308,424 remain outstanding as of June 30, 2014. As a result of this change in the terms of the awards, the outstanding RSUs are considered to be liability instruments. As a result of this modification, the Company records a liability for the fair value of the awards as of each reporting date with the change in fair value recorded through the statement of operations. The Company will record stock-based compensation expense equal to the greater of the original grant date fair value of the awards or the settlement date fair value. During the three and six months ended June 30, 2014, the Company deposited with taxing authorities approximately $58,000 and approximately $557,000, respectively, in respect of the tax liability for awards that settled during the periods.

Stock options

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

			Weighted- average price per share			Aggregate intrinsic value

Outstanding at December 31, 2013	2,388,062		$	8.66
Granted	1,802,167			12.72
Exercised	(5,715	)		1.93
Forfeited	(33,546	)		10.27


Outstanding at June 30, 2014	4,151,058		$	10.42	8.9	$	2,669,825




Exercisable at June 30, 2014	1,225,970		$	8.09	8.2	$	1,882,694




Vested and expected to vest at June 30, 2014	3,837,817		$	10.36	8.9	$	2,648,704

The fair value of each stock option is estimated on the grant date using the Black-Scholes option-pricing model using the following weighted average assumptions:

	Six months ended June 30,

	2014			2013
Risk-free interest rate		2.0	%		1.1	%
Dividend yield		—			—
Volatility		81	%		75	%
Expected term (years)		6.2			6.1

License agreements	6 Months Ended
License agreements	Jun. 30, 2014
License agreements
License agreements	7. License agreements Under the license agreement with Poniard Pharmaceuticals, Inc. ("Poniard") that the Company entered into in November 2011 relating to VS-4718 and certain other compounds, the Company paid an upfront license fee and agreed to pay Poniard milestone payments upon the achievement of specified development and regulatory milestones. In February 2014, the Company purchased the assets which were the subject of the license agreement with Poniard from Encarta, Inc. ("Encarta"), who had previously purchased these assets in 2013. In consideration for these assets, the Company issued to Encarta 97,500 shares of common stock, a warrant to purchase 142,857 shares of common stock with an exercise price equal to $17.16 per share and paid $25,000. All existing obligations under the license agreement, including an achieved development milestone and an obligation to issue a warrant, were settled as part of this transaction. The Company incurred $1.2 million of research and development expense in the first quarter of 2014 as a result of this transaction. As the warrant that was issued was consistent with the existing obligation to issue a warrant, there were no charges recorded as a result of issuing the warrant. In connection with the asset purchase agreement, the Company also assumed the rights and obligations under the license agreement by and between the Scripps Research Institute ("Scripps") and Poniard, or the Scripps License Agreement. Pursuant to the Scripps License Agreement, the Company is obligated to pay Scripps potential product development milestone payments of up to an aggregate of $3.0 million upon the achievement of specified development and regulatory milestones. In addition, the Company is obligated to pay Scripps low single-digit royalties as a percentage of net sales of licensed products, subject to adjustments in certain circumstances. The Company's obligation to pay royalties on net sales is on a country by country basis. The milestones and royalties payable to Scripps will be recorded as expense when the obligations are incurred.

Commitments and Contingencies	6 Months Ended
Commitments and Contingencies	Jun. 30, 2014
Commitments and Contingencies
Commitments and Contingencies	8. Commitments and Contingencies On April 15, 2014, the Company entered into a lease agreement for approximately 15,197 square feet of office and laboratory space in Needham, Massachusetts. The Company intends to use the leased premises as its corporate headquarters commencing in the third quarter of 2014. The lease term commenced on April 15, 2014. The Company must commence rent payments under the lease agreement on the earlier of: (i) December 1, 2014, or (ii) the first day in the calendar month after which the initial improvements to build out the leased space are substantially complete (the "Rent Commencement Date"). The lease term expires on the last day of the 60th full month following the Rent Commencement Date. The Company has agreed to pay an initial annual base rent of approximately $493,000, which base rent increases after every twelve-month period during the lease term to approximately $554,000 for the last twelve-month period. The Company is recording rent expense on a straight-line basis, beginning in April 2014. The Company also received a tenant improvement allowance of approximately $684,000 in connection with the lease. The Company has accounted for the allowance as a lease incentive, which is being recorded as a reduction to rent expense over the lease term. Deferred rent and lease incentive obligation are included in accrued expenses and other liabilities in the consolidated balance sheet. The Company has also agreed to pay its proportionate share of increases in operating expenses and property taxes for the building in which the leased space is located. The Company has provided a security deposit in the form of a letter of credit in the amount of approximately $203,000, which may be reduced to approximately $162,000 on April 15, 2016. The amount is included in restricted cash on the consolidated balance sheet.

Subsequent Events	6 Months Ended
Subsequent Events	Jun. 30, 2014
Subsequent Events
Subsequent Events	9. Subsequent Events The company reviews all activity subsequent to quarter end but prior to issuance of the condensed 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. During the period the Company did not have any material subsequent events.

Summary of significant accounting policies (Policies)	6 Months Ended
Summary of significant accounting policies (Policies)	Jun. 30, 2014
Summary of significant accounting policies
Basis of presentation	Basis of presentation The accompanying unaudited condensed consolidated financial statements of the Company have been prepared in accordance with accounting principles generally accepted in the United States ("GAAP") for interim financial reporting and as required by Regulation S-X, Rule 10-01. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (including those which are normal and recurring) considered necessary for a fair presentation of the interim financial information have been included. When preparing financial statements in conformity with GAAP, the Company must make estimates and assumptions that affect the reported amounts and related disclosures at the date of the financial statements. Actual results could differ from those estimates. Additionally, operating results for the three and six months ended June 30, 2014 are not necessarily indicative of the results that may be expected for any other interim period or for the fiscal year ending December 31, 2014. For further information, refer to the financial statements and footnotes included in the Company's Annual Report on Form 10-K for the year ended December 31, 2013 as filed with the Securities and Exchange Commission ("SEC") on March 6, 2014.
Recent Accounting Pronouncements	Recent Accounting Pronouncements On June 10, 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-10, which simplifies financial reporting for development stage entities by eliminating requirements specific to development stage entities. As a result, entities in a development stage will no longer need to present inception-to-date information about income statement line items, cash flows, and equity transactions. Instead, the new guidance clarifies how these entities should tailor existing disclosures to explain the risks and uncertainties related to their activities. This update is effective for annual periods beginning after December 15, 2014, and early application is permitted for any annual or interim period for which the entity's financial statements have not yet been issued. The Company adopted this guidance prior to issuing the financial statements in this Q2 2014 Form 10-Q. The adoption of ASU 2014-10 impacted disclosure only and did not have any impact on financial position or results of operations. There have been no changes to the Company's significant accounting policies included in the Company's Annual Report on Form 10-K for the year ended December 31, 2013 as filed with the Securities and Exchange Commission on March 6, 2014.
Subsequent Events	Subsequent Events The company reviews all activity subsequent to quarter end but prior to issuance of the condensed 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. During the period the Company did not have any material subsequent events.

Fair value of financial instruments (Tables)

6 Months Ended

Jun. 30, 2014

Fair value of financial instruments

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	$	20,732	$	14,732	$	6,000	$	—
Short-term investments		76,204		—		76,204		—
Long-term investments		5,757		—		5,757		—


Total financial assets	$	102,693	$	14,732	$	87,961	$	—




Financial liabilities
Liability classified stock-based compensation awards	$	547	$	547	$	—	$	—


Total financial liabilities	$	547	$	547	$	—	$	—

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

Financial assets
Cash equivalents	$	17,000	$	17,000	$	—	$	—
Short-term investments		82,423		—		82,423		—
Long-term investments		22,344		—		22,344		—


Total financial assets	$	121,767	$	17,000	$	104,767	$	—




Financial liabilities
Liability classified stock-based compensation awards	$	717	$	717	$	—	$	—


Total financial liabilities	$	717	$	717	$	—	$	—

Investments (Tables)

6 Months Ended

Jun. 30, 2014

Investments

Schedule of cash, cash equivalents and investments

Cash, cash equivalents and investments at June 30, 2014 and December 31, 2013 consist of the following (in thousands):

	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value

June 30, 2014
Cash and cash equivalents:
Cash and money market accounts	$	16,391	$	—	$	—		$	16,391
Corporate commercial paper		6,000		—		—			6,000


Total cash and cash equivalents	$	22,391	$	—	$	—		$	22,391


Investments:
Government-sponsored enterprise securities (due within 1 year)	$	20,219	$	8	$	—		$	20,227
Corporate bonds (due within 1 year)		55,955		25		(3	)		55,977
Corporate bonds (due within 1 - 2 years)		5,758		—		(1	)		5,757


Total investments	$	81,932	$	33	$	(4	)	$	81,961


Total cash, cash equivalents, and investments	$	104,323	$	33	$	(4	)	$	104,352

	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value

December 31, 2013
Cash and cash equivalents:
Cash and money market accounts	$	18,889	$	—	$	—		$	18,889


Total cash and cash equivalents	$	18,889	$	—	$	—		$	18,889


Investments:
Government-sponsored enterprise securities (due within 1 year)	$	30,652	$	12	$	—		$	30,664
Government-sponsored enterprise securities (due within 1 - 2 years)		4,001		2		—			4,003
Corporate bonds (due within 1 year)		51,735		30		(6	)		51,759
Corporate bonds (due within 1 - 2 years)		18,351		2		(12	)		18,341


Total investments	$	104,739	$	46	$	(18	)	$	104,767


Total cash, cash equivalents, and investments	$	123,628	$	46	$	(18	)	$	123,656

Accrued expenses (Tables)

6 Months Ended

Jun. 30, 2014

Accrued expenses

Schedule of accrued expenses

Accrued expenses consist of the following (in thousands):

	June 30, 2014		December 31, 2013

Contract research organization costs	$	2,609	$	1,918
Compensation and related benefits		969		1,687
Professional fees		275		237
License milestones		110		360
Deferred rent		72		38
Other		130		87


	$	4,165	$	4,327

Net loss per share (Tables)

6 Months Ended

Jun. 30, 2014

Net loss per share

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

	Three months ended				Six months ended
	June 30, 2014		June 30, 2013		June 30, 2014		June 30, 2013
Outstanding stock options		4,151		2,263		4,151		2,263
Unvested restricted stock		120		538		120		538
Unvested restricted stock units		394		623		394		623

Stock-based compensation (Tables)

6 Months Ended

Jun. 30, 2014

Stock-based compensation

Summary of restricted common stock activity and related information

			Weighted- average purchase price per share

Unvested at December 31, 2013	329,282		$	0.034
Vested	(208,860	)		0.022


Unvested at June 30, 2014	120,422		$	0.056

Summary of restricted stock units (RSUs) activity and related information

			Weighted- average grant date fair value

Outstanding at December 31, 2013	529,850		$	10.78
Settled	(131,798	)		10.35
Forfeited	(4,284	)		11.00


Outstanding at June 30, 2014	393,768		$	10.92

Summary of stock option activity and related information

			Weighted- average price per share			Aggregate intrinsic value

Outstanding at December 31, 2013	2,388,062		$	8.66
Granted	1,802,167			12.72
Exercised	(5,715	)		1.93
Forfeited	(33,546	)		10.27


Outstanding at June 30, 2014	4,151,058		$	10.42	8.9	$	2,669,825




Exercisable at June 30, 2014	1,225,970		$	8.09	8.2	$	1,882,694




Vested and expected to vest at June 30, 2014	3,837,817		$	10.36	8.9	$	2,648,704

Schedule of assumptions used to estimate fair value of each stock option on grant date

	Six months ended June 30,

	2014			2013
Risk-free interest rate		2.0	%		1.1	%
Dividend yield		—			—
Volatility		81	%		75	%
Expected term (years)		6.2			6.1

Fair value of financial instruments (Details) - USD ($)	3 Months Ended	6 Months Ended
Fair value of financial instruments (Details) - USD ($)	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Financial assets
Cash equivalents	$ 22,391,000	$ 22,391,000		$ 18,889,000
Short-term investments	76,204,000	76,204,000		82,423,000
Financial liabilities
Cash paid to settle restricted stock liability awards		557,000	$ 829,000
RSUs
Financial liabilities
Cash paid to settle restricted stock liability awards	58,000	557,000
Total
Financial assets
Cash equivalents	20,732,000	20,732,000		17,000,000
Short-term investments	76,204,000	76,204,000		82,423,000
Long-term investments	5,757,000	5,757,000		22,344,000
Total financial assets	102,693,000	102,693,000		121,767,000
Financial liabilities
Liability classified stock-based compensation awards	547,000	547,000		717,000
Total financial liabilities	547,000	547,000		717,000
Quoted prices in active markets (Level 1)
Financial assets
Cash equivalents	14,732,000	14,732,000		17,000,000
Total financial assets	14,732,000	14,732,000		17,000,000
Financial liabilities
Liability classified stock-based compensation awards	547,000	547,000		717,000
Total financial liabilities	547,000	547,000		717,000
Significant other observable inputs (Level 2)
Financial assets
Cash equivalents	6,000,000	6,000,000
Short-term investments	76,204,000	76,204,000		82,423,000
Long-term investments	5,757,000	5,757,000		22,344,000
Total financial assets	$ 87,961,000	$ 87,961,000		$ 104,767,000

Investments (Details) - USD ($)	3 Months Ended		6 Months Ended
Investments (Details) - USD ($)	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Investments
Charges for other-than-temporary declines in fair value of short-term or long-term investments	$ 0	$ 0	$ 0	$ 0
Unrealized gains (losses) on investments	7,000	(21,000)	1,000	(25,000)
Realized gains or losses on investments	0	0	0	0
Investments that had been in an unrealized loss position for a significant period	0		0
Investments
Cash and cash equivalents, Amortized cost	22,391,000	$ 13,880,000	22,391,000	$ 13,880,000	$ 18,889,000	$ 10,096,000
Cash and cash equivalents, Fair value	22,391,000		22,391,000		18,889,000
Investments, Amortized cost
Amortized Cost	81,932,000		81,932,000		104,739,000
Investments, Gross unrealized gains
Total cash, cash equivalents, and investments, Gross Unrealized Gains	33,000		33,000		46,000
Investments, Gross unrealized losses
Investments, Gross Unrealized Losses	(4,000)		(4,000)		(18,000)
Fair value
Investments, Fair Value	81,961,000		81,961,000		104,767,000
Total cash, cash equivalents, and investments, Amortized Cost	104,323,000		104,323,000		123,628,000
Total cash, cash equivalents, and investments, Fair Value	104,352,000		104,352,000		123,656,000
Government-sponsored enterprise securities
Investments, Amortized cost
Due within 1 year	20,219,000		20,219,000		30,652,000
Due within 1 - 2 years					4,001,000
Investments, Gross unrealized gains
Due within 1 year	8,000		8,000		12,000
Due within 1 - 2 years					2,000
Fair value
Due within 1 year	20,227,000		20,227,000		30,664,000
Due within 1 - 2 years					4,003,000
Corporate bonds
Investments, Amortized cost
Due within 1 year	55,955,000		55,955,000		51,735,000
Due within 1 - 2 years	5,758,000		5,758,000		18,351,000
Investments, Gross unrealized gains
Due within 1 year	25,000		25,000		30,000
Due within 1 - 2 years					2,000
Investments, Gross unrealized losses
Due within 1 year	(3,000)		(3,000)		(6,000)
Due within 1 - 2 years	(1,000)		(1,000)		(12,000)
Fair value
Due within 1 year	55,977,000		55,977,000		51,759,000
Due within 1 - 2 years	5,757,000		5,757,000		18,341,000
Cash and money market accounts
Investments
Cash and cash equivalents, Amortized cost	16,391,000		16,391,000		18,889,000
Cash and cash equivalents, Fair value	16,391,000		16,391,000		$ 18,889,000
Corporate commercial paper
Investments
Cash and cash equivalents, Amortized cost	6,000,000		6,000,000
Cash and cash equivalents, Fair value	$ 6,000,000		$ 6,000,000

Accrued expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2014	Dec. 31, 2013
Accrued expenses
Contract research organization costs	$ 2,609	$ 1,918
Compensation and related benefits	969	1,687
Professional fees	275	237
License milestones	110	360
Deferred rent	72	38
Other	130	87
Accrued expenses	$ 4,165	$ 4,327

Net loss per share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
Net loss per share (Details) - shares shares in Thousands	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Outstanding stock options
Net loss per share
Potentially anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	4,151	2,263	4,151	2,263
Unvested restricted stock
Net loss per share
Potentially anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	120	538	120	538
Unvested restricted stock units
Net loss per share
Potentially anti-dilutive securities excluded from calculation of diluted net loss per share (in shares)	394	623	394	623

Stock-based compensation (Details) - USD ($)			1 Months Ended	3 Months Ended		6 Months Ended
Stock-based compensation (Details) - USD ($)	Jan. 02, 2014	Jan. 02, 2013	Feb. 29, 2012	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2013
Additional disclosures
Cash used to settle restricted stock liability awards						$ 557,000	$ 829,000
2012 Plan
Stock-based compensation
Initial number of shares reserved			3,428,571
Maximum incremental number of shares reserved			571,242
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%
Increase in number of shares reserved	1,026,309	844,448
Restricted common stock
Shares
Unvested at the beginning of the period (in shares)	329,282					329,282
Vested (in shares)						(208,860)
Unvested at the end of the period (in shares)				120,422		120,422
Awards granted (in shares)				0	0	0	0
Weighted-average grant date fair value
Unvested at the beginning of the period (in dollars per share)	$ 0.034					$ 0.034
Vested (in dollars per share)						0.022
Unvested at the end of the period (in dollars per share)				$ 0.056		$ 0.056
Additional disclosures
Total unrecognized stock-based compensation expense (in dollars)				$ 296,000		$ 296,000
Weighted average period over which total unrecognized stock based compensation expense is expected to be recognized						3 months 18 days
Fair value of shares vested				$ 556,000	$ 706,000	$ 1,600,000	$ 1,500,000
RSUs
Shares
Unvested at the beginning of the period (in shares)	529,850					529,850
Settled (in shares)						(131,798)
Forfeited (in shares)						(4,284)
Unvested at the end of the period (in shares)				393,768		393,768
Awards granted (in shares)				0	0	0	0
Modified restricted stock units outstanding				308,424		308,424
Modified restricted stock units authorized								657,058
Weighted-average grant date fair value
Unvested at the beginning of the period (in dollars per share)	$ 10.78					$ 10.78
Settled (in dollars per share)						10.35
Forfeited (in dollars per share)						11.00
Unvested at the end of the period (in dollars per share)				$ 10.92		$ 10.92
Additional disclosures
Total unrecognized stock-based compensation expense (in dollars)				$ 3,100,000		$ 3,100,000
Weighted average period over which total unrecognized stock based compensation expense is expected to be recognized						1 year 7 months 6 days
Fair value of shares vested				125,000	$ 122,000	$ 1,400,000	$ 2,300,000
Cash used to settle restricted stock liability awards				$ 58,000		$ 557,000
Stock options
Shares
Forfeited (in shares)						(33,546)
Weighted-average grant date fair value
Forfeited (in dollars per share)						$ 10.27

Stock-based compensation (Details 2) - Stock options - USD ($)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Shares
Outstanding at the beginning of the period (in shares)	2,388,062
Granted (in shares)	1,802,167
Exercised (in shares)	(5,715)
Forfeited (in shares)	(33,546)
Outstanding at the end of the period (in shares)	4,151,058
Exercisable at the end of the period (in shares)	1,225,970
Vested and expected to vest at end of period (in shares)	3,837,817
Weighted-average exercise price per share
Outstanding at the beginning of the period (in dollars per share)	$ 8.66
Granted (in dollars per share)	12.72
Exercised (in dollars per share)	1.93
Forfeited (in dollars per share)	10.27
Outstanding at the end of the period (in dollars per share)	10.42
Exercisable at the end of the period (in dollars per share)	8.09
Vested and expected to vest at end of the period (in dollars per share)	$ 10.36
Weighted-average remaining contractual term
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	8 years 10 months 24 days
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	8 years 10 months 24 days
Exercisable at the end of the period	8 years 2 months 12 days
Vested and expected to vest at the end of the period	8 years 10 months 24 days
Aggregate intrinsic value
Outstanding at the end of the period (in dollars)	$ 2,669,825
Exercisable at the end of the period (in dollars)	1,882,694
Vested and expected to vest at end of the period (in dollars)	$ 2,648,704
Assumptions used to estimate fair value of each stock-based award on the grant date
Risk-free interest rate (as a percent)	2.00%	1.10%
Volatility (as a percent)	81.00%	75.00%
Expected term	6 years 2 months 12 days	6 years 1 month 6 days

License agreements (Details)	1 Months Ended	3 Months Ended			6 Months Ended
License agreements (Details)	Feb. 28, 2014 USD ($) $ / shares shares	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Jun. 30, 2013 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2013 USD ($)
License agreements
Research and development expense		$ 8,305,000		$ 6,045,000	$ 16,716,000	$ 11,341,000
Warrant issuance charges					$ 0
Exclusive license agreement
License agreements
Research and development expense			$ 1,200,000
Exclusive license agreement \| Encarta, Inc.
License agreements
Common stock issued (in shares) \| shares	97,500
Number of shares of common stock in the warrant issued under the license agreement \| shares	142,857
Exercise price of shares of common stock in the warrant issued under the license agreement (in dollars per share) \| $ / shares	17.16
Exclusive license agreement \| Scripps
License agreements
Milestone payments upon the achievement of specified development and regulatory milestones	$ 3,000,000
Asset purchase agreement \| Encarta, Inc.
License agreements
Cash payment made under the agreement	$ 25,000

Commitments and Contingencies (Details) - Intercontinental Fund III 117 Kendrick Street, LLC	Apr. 15, 2014 USD ($) ft²	Apr. 15, 2016 USD ($)	Jun. 30, 2014 USD ($)
Lease
Area of space \| ft²	15,197
Lease term	60 months
Initial annual base rent	$ 493,000
Period after which base rent increases	12 months
Base rent for last twelve-month period	$ 554,000
Tenant improvement allowance			$ 684,000
Letter of credit
Lease
Security deposit	$ 203,000
Letter of credit \| Subsequent events
Lease
Security deposit		$ 162,000