Document and Entity Information	6 Months Ended
Document and Entity Information	Jun. 30, 2012	Aug. 10, 2012
Document and Entity Information
Entity Registrant Name	Verastem, Inc.
Entity Central Index Key	0001526119
Document Type	10-Q
Document Period End Date	Jun. 30, 2012
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		21,251,128
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q2

CONDENSED BALANCE SHEETS (USD $)	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 15,751,000	$ 20,954,000
Short-term investments	22,937,000	26,857,000
Prepaid expenses and other current assets	509,000	130,000
Total current assets	39,197,000	47,941,000
Property and equipment, net	782,000	709,000
Long-term investments	65,599,000	8,994,000
Other assets		1,307,000
Restricted cash	86,000	86,000
Total assets	105,664,000	59,037,000
Current liabilities:
Accounts payable	2,450,000	2,273,000
Accrued expenses	763,000	873,000
Total current liabilities	3,213,000	3,146,000
Deferred rent	57,000	74,000
Liability for shares subject to repurchase	25,000	36,000
Obligation to issue warrant		406,000
Stockholders' equity (deficit)
Preferred stock, $0.0001 par value; 5,000 shares authorized; none issued
Common stock, $0.0001 par value; 100,000 and 53,093, shares authorized at June 30, 2012 and December 31, 2011, respectively, 21,059 and 1,559 shares issued and outstanding at June 30, 2012 and December 31, 2011, respectively	2,000	1,000
Additional paid-in capital	130,541,000	1,702,000
Accumulated other comprehensive loss	(11,000)	(2,000)
Deficit accumulated during the development stage	(28,163,000)	(14,467,000)
Total stockholders' equity (deficit)	102,369,000	(12,766,000)
Total liabilities, redeemable convertible preferred stock and stockholders' equity (deficit)	105,664,000	59,037,000
Series A redeemable convertible preferred stock
Current liabilities:
Redeemable convertible preferred stock		15,939,000
Series B redeemable convertible preferred stock
Current liabilities:
Redeemable convertible preferred stock		31,948,000
Series C redeemable convertible preferred stock
Current liabilities:
Redeemable convertible preferred stock		$ 20,254,000

CONDENSED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Series A redeemable convertible preferred stock	Dec. 31, 2011 Series A redeemable convertible preferred stock	Jun. 30, 2012 Series B redeemable convertible preferred stock	Dec. 31, 2011 Series B redeemable convertible preferred stock	Jun. 30, 2012 Series C redeemable convertible preferred stock	Dec. 31, 2011 Series C redeemable convertible preferred stock
Redeemable convertible preferred stock, par value (in dollars per share)			$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized				16,000		16,025		9,068
Redeemable convertible preferred stock, shares issued				16,000		16,025		9,068
Redeemable convertible preferred stock, shares outstanding				16,000		16,025		9,068
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares issued	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	21,059	1,559
Common stock, shares outstanding	21,059	1,559

CONDENSED STATEMENTS OF COMPREHENSIVE LOSS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended		23 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012
Operating expenses:
Research and development	$ 4,683	$ 1,726	$ 9,486	$ 2,401	$ 19,769
General and administrative	2,213	759	4,338	1,230	8,537
Total operating expenses	6,896	2,485	13,824	3,631	28,306
Loss from operations	(6,896)	(2,485)	(13,824)	(3,631)	(28,306)
Interest income	71		128		143
Net loss	(6,825)	(2,485)	(13,696)	(3,631)	(28,163)
Accretion of preferred stock		(4)	(6)	(8)	(40)
Net loss applicable to common stockholders	(6,825)	(2,489)	(13,702)	(3,639)	(28,203)
Net loss per share applicable to common stockholders-basic and diluted (in dollars per share)	$ (0.34)	$ (2.03)	$ (0.79)	$ (3.14)	$ (5.20)
Weighted-average number of common shares used in net loss per share applicable to common stockholders-basic and diluted (in shares)	19,863	1,225	17,278	1,158	5,425
Comprehensive loss	$ (6,791)	$ (2,485)	$ (13,705)	$ (3,631)	$ (28,174)

CONDENSED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended		23 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012
Operating activities
Net loss	$ (13,696)	$ (3,631)	$ (28,163)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	94	11	177
Stock-based compensation expense	3,012	91	4,699
Common stock issued in exchange for license			46
Obligation to issue a warrant in exchange for license			439
Change in fair value of obligation to issue warrant	431		398
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(379)	(79)	(509)
Other assets		(75)
Accounts payable	177	934	2,450
Accrued expenses and deferred rent	420	1,720	820
Net cash used in operating activities	(9,941)	(1,029)	(19,643)
Investing activities
Purchases of property and equipment	(167)	(385)	(960)
Purchases of investments	(116,923)		(152,774)
Maturities of investments	64,229		64,229
Increase in restricted cash		(86)	(86)
Net cash used in investing activities	(52,861)	(471)	(89,591)
Financing activities
Proceeds from issuance of redeemable convertible preferred stock		12,000	68,107
Net proceeds from the issuance of common stock and restricted common stock	57,599	72	56,878
Net cash provided by financing activities	57,599	12,072	124,985
Increase (decrease) in cash and cash equivalents	(5,203)	10,572	15,751
Cash and cash equivalents at beginning of period	20,954	3,584
Cash and cash equivalents at end of period	15,751	14,156	15,751
Supplemental disclosure of non-cash financing activity
Accretion of redeemable convertible preferred stock to redemption value	6	8	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

Summary of significant accounting policies

6 Months Ended

Jun. 30, 2012

Summary of significant accounting policies

Summary of significant accounting policies

1. Summary of significant accounting policies

Basis of presentation

The accompanying unaudited condensed 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, consisting only of normal and recurring adjustments, 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 of assets, liabilities, revenues, expenses 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, 2012 are not necessarily indicative of the results that may be expected for any other interim period or for the fiscal year ending December 31, 2012. 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, 2011 as filed with the Securities and Exchange Commission ("SEC") on March 30, 2012.

Fair value of financial instruments

6 Months Ended

Jun. 30, 2012

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 that have been measured at fair value at June 30, 2012 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	$	4,412	$	4,412	$	—	$	—
Short-term investments		22,937		—		22,937		—
Long-term investments		65,599		—		65,599		—

Total financial assets	$	92,948	$	4,412	$	88,536	$	—

The following table presents information about the Company's financial assets and liabilities 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

The Company's cash equivalents and investments are comprised of money market accounts, government-sponsored enterprise securities and commercial paper of publicly traded companies secured by the U.S. government. 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, 2012 or December 31, 2011.

In connection with the license with Poniard Pharmaceuticals Inc., 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 an 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 is a level 3 liability because its value measurement is 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 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.

Fair value of financial instruments (Details 2) (USD $)	6 Months Ended	23 Months Ended				1 Months Ended	6 Months Ended			12 Months Ended
Fair value of financial instruments (Details 2) (USD $)	Jun. 30, 2012	Jun. 30, 2012	Feb. 29, 2012	Dec. 31, 2011	Dec. 31, 2011 Significant unobservable inputs (Level 3)	Jan. 31, 2012 Poniard Pharmaceuticals Inc.	Jun. 30, 2012 Poniard Pharmaceuticals Inc.	Jan. 26, 2012 Poniard Pharmaceuticals Inc.	Dec. 31, 2011 Poniard Pharmaceuticals Inc. Significant unobservable inputs (Level 3)	Dec. 31, 2011 Poniard Pharmaceuticals Inc. Significant unobservable inputs (Level 3) Non-IPO	Dec. 31, 2011 Poniard Pharmaceuticals Inc. Significant unobservable inputs (Level 3) IPO
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
Exercise price (in dollars per share)								$ 11.09		$ 6.86	$ 10.00
Estimated stock price contingent upon milestone achievement (in dollars per share)			$ 10.00					$ 12.60		$ 3.22	$ 8.54
Expected term						4 years				4 years 1 month 6 days	4 years 1 month 6 days
Volatility (as a percent)						75.00%				70.00%	70.00%
Dividend yield (as a percent)						0.00%				0.00%	0.00%
Risk-free rate (as a percent)						0.54%				0.60%	0.60%
Probability of achieving milestone (as a percent)						80.00%	100.00%			80.00%	80.00%
Probability of scenario (as a percent)						100.00%				20.00%	80.00%
Obligation to issue warrant				$ 406,000	$ 406,000			$ 837,000	$ 406,000
Increase in fair value of obligation to issue the warrant	$ 431,000	$ 398,000				$ 431,000

Investments (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2010
Investments
Cash and cash equivalents, Amortized Cost	$ 15,751	$ 20,954	$ 14,156	$ 3,584
Cash and cash equivalents, Fair Value		20,954
Investments, Amortized Cost
Amortized Cost	88,547	35,852
Investments, Gross Unrealized Gains
Gross Unrealized Gains	19	6
Investments, Gross Unrealized Losses
Investments, Gross Unrealized Losses	(30)	(7)
Fair Value
Investments, Fair Value	88,536	35,851
Total cash, cash equivalents, and investments, Amortized Cost	104,298	56,806
Total cash, cash equivalents, and investments, Fair Value	104,287	56,805
Government-sponsored enterprise securities
Investments, Amortized Cost
Due within 1 year	17,912	10,900
Due within 1 - 2 years	65,603	8,998
Investments, Gross Unrealized Gains
Due within 1 year		2
Due within 1 - 2 years	19	1
Investments, Gross Unrealized Losses
Due within 1 year	(6)	(1)
Due within 1 - 2 years	(23)	(5)
Fair Value
Due within 1 year	17,906	10,901
Due within 1 - 2 years	65,599	8,994
Commercial paper secured by the U.S. government
Investments, Amortized Cost
Due within 1 year	5,032	15,954
Investments, Gross Unrealized Gains
Due within 1 year		3
Investments, Gross Unrealized Losses
Due within 1 year	(1)	(1)
Fair Value
Due within 1 year	5,031	15,956
Cash and money market accounts
Investments
Cash and cash equivalents, Amortized Cost	15,751	19,954
Cash and cash equivalents, Fair Value	15,751	19,954
Government-sponsored enterprise securities
Investments
Cash and cash equivalents, Amortized Cost		1,000
Cash and cash equivalents, Fair Value		$ 1,000

Prepaid expenses and other current assets (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Prepaid expenses and other current assets
Prepaid insurance	$ 207
Prepaid other expense	169	77
Interest receivable	133	53
Prepaid expenses and other current assets	$ 509	$ 130

Accrued expenses (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Accrued expenses
Compensation and related benefits	$ 496	$ 86
Professional fees	133	520
Contract research organizations	63	217
Other expenses	39	23
Deferred rent	32	27
Accrued expenses	$ 763	$ 873

Common stock (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended
	Feb. 29, 2012	Jan. 31, 2012
Reverse Stock Split
Reverse stock spilt conversion ratio for common stock		3.5
Initial Public Offering
Common stock registered sold (in shares)	6,325,000
Selling price per share (in dollars per share)	$ 10.00
Net proceeds of IPO	$ 56.8

Stock-based compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	6 Months Ended
	Feb. 29, 2012	Jun. 30, 2012
Stock-based compensation
Initial number of shares reserved	3,428,571
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%
Restricted stock
Shares
Unvested at the beginning of the period (in shares)		1,435,000
Vested (in shares)		(292,000)
Unvested at the end of the period (in shares)		1,143,000
Weighted-average grant date fair value
Unvested at the end of the period (in dollars per share)		$ 0.025
Vested (in dollars per shares)		$ 0.039
Unvested at the beginning of the period (in dollars per share)		$ 0.022
Additional disclosures
Total unrecognized stock-based compensation expense (in dollars)		$ 7.7
Weighted-average recognition period		2 years 3 months 18 days
RSUs
Shares
Granted (in shares)		600,000
Cancelled (in shares)		(2,000)
Unvested at the end of the period (in shares)		598,000
Weighted-average grant date fair value
Granted (in dollars per shares)		$ 11.10
Cancelled (in dollars per shares)		$ 11.10
Unvested at the beginning of the period (in dollars per share)		$ 11.10
Additional disclosures
Total unrecognized stock-based compensation expense (in dollars)		$ 5.9
Weighted-average recognition period		3 years 7 months 6 days

*Significant Transactions (Details) (Dual inhibitors of PI3K and mTOR, including related patent right agreement, SBio Pte Ltd, USD $)**	1 Months Ended	6 Months Ended
	May 31, 2012	Jun. 30, 2012
Collaborative agreement
Upfront fee paid	$ 350,000
Maximum
Collaborative agreement
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%

Subsequent Events (Details) (Subsequent events, Pfizer Inc, USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended
	Jul. 31, 2012
Subsequent events \| Pfizer Inc
Subsequent Events
One-time cash payment	$ 1.5
Common stock issued	192,012
Eligible amount receivable on developmental milestones by Pfizer	2
Additional payable on successful attainment of regulatory and commercial sales milestones	$ 125
Royalty obligations term	10 years