Sage Therapeutics (SAGE) 10-Q 14 Aug 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Jun. 30, 2014	Aug. 01, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Jun-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
Trading Symbol	'SAGE	'
Entity Registrant Name	'Sage Therapeutics, Inc.	'
Entity Central Index Key	'0001597553	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	25,711,926

Balance_Sheets

Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$49,127	$8,066
Prepaid expenses and other current assets	2,416	341
Total current assets	51,543	8,407
Property and equipment, net	69	86
Restricted cash	39	39
Total assets	51,651	8,532
Current liabilities:	'	'
Accounts payable	1,862	1,988
Accrued expenses	2,069	327
Total current liabilities	3,931	2,315
Other liabilities:	40	44
Total liabilities	3,971	2,359
Redeemable convertible preferred stock	92,472	37,709
Stockholders' deficit:	'	'
Common stock, $0.0001 par value; 70,623,905 and 66,000,000 shares authorized at June 30, 2014 and December 31, 2013, respectively; 1,714,248 and 1,622,761 shares issued and outstanding at June 30, 2014 and December 31, 2013, respectively	'	'
Additional paid-in capital	'	139
Accumulated deficit	-44,792	-31,675
Total stockholders deficit	-44,792	-31,536
Total liabilities, redeemable convertible preferred stock and stockholders' deficit	$51,651	$8,532

Balance_Sheets_Parenthetical

Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement Of Financial Position [Abstract]	'	'
Redeemable convertible preferred stock, par value	$0.00	$0.00
Redeemable convertible preferred stock, shares authorized	56,723,905	37,750,000
Redeemable convertible preferred stock, shares issued	56,723,904	37,750,000
Redeemable convertible preferred stock, shares outstanding	56,723,904	37,750,000
Redeemable convertible preferred stock, liquidation preference	$96,615	$40,663
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	70,623,905	66,000,000
Common stock, shares issued	1,714,248	1,622,761
Common stock, shares outstanding	1,714,248	1,622,761

Statements_of_Operations_and_C

Statements of Operations and Comprehensive Loss (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Operating expenses:	'	'	'	'
Research and development	$4,381	$3,854	$8,554	$6,437
General and administrative	1,807	801	3,424	1,607
Total operating expenses	6,188	4,655	11,978	8,044
Loss from operations	-6,188	-4,655	-11,978	-8,044
Interest income (expense), net	1	'	1	'
Other income (expense), net	-5	'	-5	'
Net loss and comprehensive loss	-6,192	-4,655	-11,982	-8,044
Accretion of redeemable convertible preferred stock to redemption value	-1,577	'	-1,903	'
Net loss attributable to common stockholders	($7,769)	($4,655)	($13,885)	($8,044)
Net loss per share attributable to common stockholders-basic and diluted	($4.57)	($3.18)	($8.28)	($5.58)
Weighted average number of common shares used in net loss per share attributable to common stockholders-basic and diluted	1,700,517	1,464,419	1,676,864	1,442,774

Statement_of_Changes_in_Redeem

Statement of Changes in Redeemable Convertible Preferred Stock and Stockholders' Deficit (USD $)	Total	Series A, B and C Redeemable Convertible Preferred Stock [Member]	Series A, B and C Redeemable Convertible Preferred Stock [Member]	Series A, B and C Redeemable Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]
In Thousands, except Share data	USD ($)	USD ($)	Series B Preferred Stock [Member]	Series C Preferred Stock [Member]		USD ($)	USD ($)
			USD ($)	USD ($)
Balances at Dec. 31, 2013	($31,536)	$37,709	'	'	'	$139	($31,675)
Balances, Shares at Dec. 31, 2013	'	37,750,000	'	'	1,622,761	'	'
Issuance of Preferred stock, net of issuance costs, Amount	'	'	14,970	37,890	'	'	'
Issuance of Preferred stock, net of issuance costs, Shares	'	'	9,999,999	8,973,905	'	'	'
Issuance of common stock from exercise of stock options, Amount	2	'	'	'	'	2	'
Issuance of common stock from exercise of stock options, Shares	'	'	'	'	3,968	'	'
Vesting of restricted stock, Amount	5	'	'	'	'	5	'
Vesting of restricted stock, Shares	'	'	'	'	71,647	'	'
Issuance of common stock in payment of consultant fees, Amount	127	'	'	'	'	127	'
Issuance of common stock in payment of consultant fees, Shares	'	'	'	'	15,872	'	'
Stock-based compensation expense	495	'	'	'	'	495	'
Accretion of redeemable convertible preferred stock to redemption value	-1,903	1,903	'	'	'	-768	-1,135
Net loss	-11,982	'	'	'	'	'	-11,982
Balances at Jun. 30, 2014	($44,792)	$92,472	'	'	'	'	($44,792)
Balances, Shares at Jun. 30, 2014	'	56,723,904	'	'	1,714,248	'	'

Statement_of_Changes_in_Redeem1

Statement of Changes in Redeemable Convertible Preferred Stock and Stockholders' Deficit (Parenthetical) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014
Series B Preferred Stock [Member]	'
Preferred Stock, issuance costs	$30
Series C Preferred Stock [Member]	'
Preferred Stock, issuance costs	$110

Statements_of_Cash_Flows

Statements of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities	'	'
Net loss	($11,982)	($8,044)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Stock-based compensation expense	495	12
Licensing or consulting fees paid in common stock	127	'
Depreciation and amortization	22	23
Changes in operating assets and liabilities	'	'
Prepaid expenses and other current assets	-435	-33
Accounts payable	-385	525
Accrued expenses and other	1,269	211
Net cash used in operating activities	-10,889	-7,306
Cash flows from investing activities	'	'
Purchase of property and equipment	-5	-3
Net cash used in investing activities	-5	-3
Cash flows from financing activities	'	'
Proceeds from the issuance of common stock and restricted stock	2	35
Payment of offering costs	-907	'
Net cash provided by financing activities	51,955	5,030
Net increase (decrease) in cash and cash equivalents	41,061	-2,279
Cash and cash equivalents at beginning of period	8,066	2,802
Cash and cash equivalents at end of period	49,127	523
Supplemental disclosure of non-cash investing and financing activities	'	'
Accretion of redeemable convertible preferred stock to redemption value	1,903	'
Deferred initial public offering costs included in accounts payable or accrued expenses	733	'
Series A Preferred Stock [Member]	'	'
Cash flows from financing activities	'	'
Proceeds from the issuance of preferred stock, net of issuance costs	'	4,995
Series B Preferred Stock [Member]	'	'
Cash flows from financing activities	'	'
Proceeds from the issuance of preferred stock, net of issuance costs	14,970	'
Series C Preferred Stock [Member]	'	'
Cash flows from financing activities	'	'
Proceeds from the issuance of preferred stock, net of issuance costs	$37,890	'

Nature_of_the_Business

Nature of the Business	6 Months Ended
	Jun. 30, 2014
Accounting Policies [Abstract]	'
Nature of the Business	'
	1	Nature of the Business
	Sage Therapeutics, Inc. (“Sage” or the “Company”) is a clinical-stage biopharmaceutical company committed to developing and commercializing novel medicines to treat life-threatening, rare central nervous system (“CNS”) disorders, where there are inadequate or no approved existing therapies. The Company is targeting CNS indications where patient populations are easily identified, acute treatment is typically initiated in the hospital setting, clinical endpoints are well-defined, and development pathways are feasible. This focus allows the Company to make highly informed decisions when advancing its product candidates through the development process. The Company’s initial product candidates are aimed at treating different stages of status epilepticus, a life-threatening condition in which the brain is in a state of persistent seizure.
	The Company was incorporated under the laws of the state of Delaware on April 16, 2010 and commenced operations on January 19, 2011 as Sterogen Biopharma, Inc. On September 13, 2011, the Company changed its name to Sage Therapeutics, Inc. under its second Amended and Restated Certificate of Incorporation.
	The Company is subject to risks and uncertainties common to early-stage companies in the biotech industry, including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations, and ability to secure additional capital to fund operations.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	2	Summary of Significant Accounting Policies
	Basis of Presentation
	The unaudited interim financial statements of the Company included herein have been prepared, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these consolidated financial statements should be read in conjunction with the financial statements as of and for the year ended December 31, 2013 and the three months ended March 31, 2014 and notes thereto, included in the Company’s prospectus filed with the SEC pursuant to Rule 424(b)(4) on July 18, 2014 (the “Prospectus”).
	The unaudited interim financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of the Company’s management, the accompanying unaudited interim consolidated financial statements contain all adjustments which are necessary to present fairly the Company’s financial position as of June 30, 2014, the results of its operations for the three and six months ended June 30, 2014 and 2013 and its cash flows for the six months ended June 30, 2014 and 2013. Such adjustments are of a normal and recurring nature. The results for the six months ended June 30, 2014 are not necessarily indicative of the results for the year ending December 31, 2014, or for any future period.
	On July 23, 2014, the Company completed the sale of 5,750,000 shares of its common stock in its initial public offering (the “IPO”), at a price to the public of $18.00 per share, resulting in net proceeds to the Company of $94.0 million after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company. In preparation for the IPO, the Company’s board of directors and stockholders approved a 1-for-3.15 reverse stock split of the Company’s common stock effective July 2, 2014. All share and per share amounts in the unaudited financial statements contained herein and notes thereto have been retroactively adjusted, where necessary, to give effect to this reverse stock split. In connection with the closing of the IPO, all of the Company’s outstanding redeemable convertible preferred stock automatically converted into shares of common stock as of July 23, 2014, resulting in the issuance by the Company of an additional 18,007,575 shares of common stock. The significant increase in shares outstanding in July 2014 is expected to impact the year-over-year comparability of the Company’s net loss per share calculations over the next year.
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	Fair Value Measurements
	Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three categories:
	Level 1 -		Quoted market prices in active markets for identical assets or liabilities. At June 30, 2014 (unaudited) and December 31, 2013, the Company’s Level 1 assets consisted of a money market fund totaling $49,548 and $8,024, respectively.
	Level 2 -		Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. At June 30, 2014 (unaudited) and December 31, 2013, the Company had no Level 2 assets or liabilities.
	Level 3 -		Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. At June 30, 2014 (unaudited) and December 31, 2013, the Company had no Level 3 assets or liabilities.
	The Company’s financial instruments generally consist of cash equivalents, accounts payable and accrued expenses. The carrying amounts for the applicable financial instruments reported in the balance sheets approximate their fair values at June 30, 2014 (unaudited).
	Deferred Offering Costs
	The Company capitalizes certain legal, accounting and other third-party fees that are directly associated with in-process equity financings as other assets until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ equity (deficit) as a reduction of additional paid-in capital generated as a result of the offering. As of June 30, 2014 (unaudited), the Company recorded $1,640 of deferred offering costs, included in prepaid expenses and other current assets in the accompanying consolidated balance sheet, in contemplation of its July 2014 IPO. The Company did not record any deferred offering costs as of December 31, 2013.
	Recently Issued Accounting Pronouncements
	In June 2014, the FASB issued guidance that removes all incremental reporting requirements for development stage entities, including the requirement to report inception-to-date information in the statements of income, cash flows, and shareholders' equity. These changes become effective for the Company on January 1, 2015 and early adoption is permitted. The Company elected to early adopt this guidance for the period ended June 30, 2014. The adoption of this guidance resulted in decreased financial statement disclosures, but did not impact the Company’s financial condition, results of operations or cash flows.
	There have been no other material changes to the significant accounting policies previously disclosed in the Company’s Prospectus.

Accrued_Expenses

Accrued Expenses	6 Months Ended
	Jun. 30, 2014
Text Block [Abstract]	'
Accrued Expenses	'
	3	Accrued Expenses
	Accrued expenses consist of the following:
			June 30, 2014		December 31, 2013
	Employee related expenses		$	674	$	49
	Development & clinical costs			686		57
	Professional services			210		190
	Initial public offering costs			474		—
	Other accrued expenses			25		31
	Total accrued expenses		$	2,069	$	327

StockBased_Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation	'
	4	Stock-Based Compensation
	The Company maintains the 2011 Stock Option and Incentive Plan (the “2011 Stock Option Plan”) which provides for the grant of restricted stock awards, incentive stock options and non-statutory stock options to purchase up to 3,142,857 shares of the Company’s common stock to employees, officers, directors and consultants of the Company. At June 30, 2014, there were 648,952 shares available for future issuance under the 2011 Stock Option Plan.
	Terms of restricted stock awards and stock option agreements, including vesting requirements, are determined by the Board of Directors, subject to the provisions of the 2011 Stock Option Plan. Options and restricted stock awards granted by the Company generally vest based on the grantee’s continued service with the Company during a specified period following grant. Awards generally vest ratably over four years, with 25% cliff vesting at the one-year anniversary for new employee awards. During 2013, the Company also granted a pool of option awards which vest ratably over one year. All awards are exercisable from the date of grant for a period of ten years. The stock-based compensation expense recognized during the three and six months ended June 30, 2014 and 2013 was as follows:
			Three Months Ended June 30,						Six Months Ended June 30,
			2014			2013			2014		2013
	Stock compensation expense:
	Research and development		$	153		$	8		$	259	$	12
	General and administrative			182			—			236		—
			$	335		$	8		$	495	$	12
	For stock option awards, the fair value of the options is estimated at the grant date using the Black-Scholes option-pricing model, taking into account the terms and conditions upon which options are granted. The fair value of the options is amortized on a straight-line basis over the requisite service period of the awards. The weighted average grant date fair value per share relating to outstanding stock options granted under the 2011 Stock Option Plan during the three and six months ended June 30, 2014 was $9.61 and $8.90, respectively.
	The fair value of each option granted to employees and directors during the three and six months ended June 30, 2014 under the 2011 Stock Option Plan has been calculated on the date of grant using the following weighted average assumptions:
			Three Months Ended			Six Months Ended
			30-Jun-14			30-Jun-14
	Expected dividend yield			0	%		0	%
	Expected volatility			102.15	%		100.88
	Risk free interest rate			1.82	%		1.9	%
	Expected term			6.06 years			6.02 years
	Expected dividend yield: The Company has not paid and does not anticipate paying any dividends in the foreseeable future.
	Risk-free interest rate: The Company determined the risk-free interest rate by using a weighted average equivalent to the expected term based on the U.S. Treasury yield curve in effect as of the date of grant.
	Expected volatility: As the Company had been operating as a private company, there is not sufficient historical volatility for the expected term of the options. Therefore, the Company used an average historical share price volatility based on an analysis of reported data for a peer group of comparable companies.
	Expected term (in years): Expected term represents the period that the Company’s share option grants are expected to be outstanding. As the Company had been operating as a private company, there is not sufficient historical share data to calculate the expected term of the options. Therefore, the Company elected to utilize the “simplified” method to value share option grants issued to employees. Under this approach, the weighted average expected life is presumed to be the average of the vesting term and the contractual term of the option.
	Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from estimates. The Company estimates forfeitures based on historical termination behavior. For the three and six months ended June 30, 2014, a forfeiture rate of 10% was applied.
	For options granted to nonemployees, the expected life of the option used is ten years, which is the contractual term of each such option. All other assumptions used to calculate the grant date fair value are generally consistent with the assumptions used for options granted to employees.
	The table below summarizes activity related to stock options:
						Weighted-			Weighted-Average
						Average			Remaining Life (in		Aggregate Intrinsic
			Shares			Exercise Price			years)		Value
	Outstanding as of December 31, 2013			1,203,481		$	0.51			9.6	$	1,038
	Granted			680,940			6.77
	Exercised			(3,968	)		0.44
	Forfeited			(20,634	)		1.35
	Outstanding as of June 30, 2014			1,859,819		$	2.78			9.35	$	28,281
	Vested or expected to vest as of June 30, 2014			1,617,115		$	2.66			9.33	$	24,783
	Exercisable as of June 30, 2014			80,201		$	1.09			9.11	$	1,355
	As of June 30, 2014, the Company had unrecognized stock-based compensation expense related to its unvested stock option awards of $4,953, which is expected to be recognized over the remaining weighted average vesting period of 3.36 years. The total fair value of shares vested for the six months ended June 30, 2014 was $219. During the six months ended June 30, 2014, stock option exercises resulted in proceeds of $2. The intrinsic value of stock options exercised during the six months ended June 30, 2014 was $30.
	Restricted Stock Awards
	During the six months ended June 30, 2014, the Company granted restricted stock awards to certain officers, employees, directors, and consultants of the Company. During the three and six months ended June 30, 2014, the Company recorded $33 and $55, respectively, of stock-based compensation expense related to its restricted stock.
	The table below summarizes activity relating to restricted stock:
						Weighted
						Average Grant
			Shares			Date Fair Value
	Unvested restricted common stock as of December 31, 2013			315,718		$	—
	Issued			—			—
	Vested			(71,647	)		—
	Forfeited			—			—
	Repurchased			(6,778	)		—
	Unvested restricted common stock as of June 30, 2014			237,293			—
	As of June 30, 2014, the Company had unrecognized stock-based compensation expense related to its unvested restricted stock awards of $239, which is expected to be recognized over the remaining weighted average vesting period of 1.64 years.
	Unvested shares are subject to repurchase by the Company, at the issuance price, upon the employee’s termination at the Company’s sole discretion. In the six months ended June 30, 2014, the Company repurchased 6,778 shares of restricted common stock issued to employees with a value of less than $1 in conjunction with the employees’ termination from the Company.

Net_Loss_Per_Share

Net Loss Per Share	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Net Loss Per Share	'
	5	Net Loss Per Share
	The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders for the three and six months ended June 30, 2014 and 2013:
			Three Months Ended June 30,						Six Months Ended June 30,
			2014			2013			2014			2013
	Numerator:
	Net loss attributable to common stockholders		$	(7,769	)	$	(4,655	)	$	(13,885	)	$	(8,044	)
	Denominator:
	Weighted average common shares outstanding—basic			1,700,517			1,464,419			1,676,864			1,442,774
	Dilutive effect of common share equivalents resulting from common share options and preferred common shares (as converted)			—			—			—			—
	Weighted average common shares outstanding—diluted			1,700,517			1,464,419			1,676,864			1,442,774
	Net loss per share attributable to common stockholders—basic and diluted		$	(4.57	)	$	(3.18	)	$	(8.28	)	$	(5.58	)
	The following common stock equivalents, presented on a weighted average basis, were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive:
			Three Months Ended June 30,						Six Months Ended June 30,
			2014			2013			2014			2013
	Options to purchase common stock			1,595,481			—			1,595,481			—
	Restricted stock			235,247			274,798			235,265			274,795
	Convertible preferred stock (as converted to common stock)			18,007,575			6,349,204			16,572,562			5,855,143
				19,838,303			6,624,002			18,403,308			6,129,938

Income_Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	6	Income Taxes
	The Company did not record a federal or state income tax benefit for the Company’s losses for the six months ended June 30, 2014 and 2013 due to the Company’s conclusion that a valuation allowance is required.

Related_Party_Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2014
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	7	Related Party Transactions
	Since inception, the Company has received consulting and management services from Third Rock Ventures LLC, which through its affiliates, has a controlling interest in the Company and owns Series A, B and C preferred stock and common stock at June 30, 2014. The Company paid Third Rock Ventures LLC $99 and $190 for these services during the three months ended June 30, 2014 and 2013, respectively. The Company paid Third Rock Ventures LLC $224 and $403 for these services during the six months ended June 30, 2014 and 2013, respectively. The Company owed to Third Rock Ventures LLC $31 at June 30, 2014. This amount is included in Accounts Payable.

Subsequent_Events

Subsequent Events	6 Months Ended
	Jun. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	8	Subsequent Events
	2014 Stock Option Plan
	On July 2, 2014, the Company’s stockholders approved the 2014 Stock Option and Incentive Plan (the “2014 Stock Option Plan”), which became effective upon the completion of the IPO. The 2014 Stock Option Plan replaced the 2011 Stock Option Plan. Any options or awards outstanding under the Company’s 2011 Stock Option Plan remained outstanding and effective. The 2014 Stock Option Plan provides for the grant of stock options, stock appreciation rights, restricted stock, restricted stock units, unrestricted stock, performance-share awards and cash-based awards. The number of shares initially reserved for issuance under the 2014 Stock Option Plan is the sum of (i) 1,143,000 shares of common stock and (ii) the number of shares under the 2011 Stock Option Plan that are not needed to fulfill the Company’s obligations for awards issued under the 2011 Stock Option Plan as a result of forfeiture, expiration, cancellation, termination or net issuances of awards thereunder. The number of shares of common stock that may be issued under the 2014 Stock Option Plan is also subject to increase on the first day of each fiscal year by up to 4% of the Company’s issued and outstanding shares of common stock on the immediately preceding December 31.
	2014 Employee Stock Purchase Plan
	On July 2, 2014, the Company’s stockholders approved the 2014 Employee Stock Purchase Plan. A total of 282,000 shares of common stock were initially authorized for issuance under this plan. The 2014 Employee Stock Purchase Plan became effective upon the completion of the IPO.
	Initial Public Offering
	On July 23, 2014, the Company completed the sale of 5,750,000 shares of its common stock in its IPO, at a price to the public of $18.00 per share, resulting in net proceeds to the Company of $94.0 million after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company.
	In preparation for the IPO, the Company’s board of directors and stockholders approved a 1-for-3.15 reverse stock split of the Company’s common stock effective July 2, 2014. All share and per share amounts in the unaudited consolidated financial statements contained herein and notes thereto have been retroactively adjusted, where necessary, to give effect to this reverse stock split. In connection with the closing of the IPO, all of the Company’s outstanding redeemable convertible preferred stock automatically converted into shares of common stock as of July 23, 2014, resulting in the issuance by the Company of an additional 18,007,575 shares of common stock.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2014
Accounting Policies [Abstract]	'
Basis of Presentation	'
	Basis of Presentation
	The unaudited interim financial statements of the Company included herein have been prepared, pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted from this report, as is permitted by such rules and regulations. Accordingly, these consolidated financial statements should be read in conjunction with the financial statements as of and for the year ended December 31, 2013 and the three months ended March 31, 2014 and notes thereto, included in the Company’s prospectus filed with the SEC pursuant to Rule 424(b)(4) on July 18, 2014 (the “Prospectus”).
	The unaudited interim financial statements have been prepared on the same basis as the audited consolidated financial statements. In the opinion of the Company’s management, the accompanying unaudited interim consolidated financial statements contain all adjustments which are necessary to present fairly the Company’s financial position as of June 30, 2014, the results of its operations for the three and six months ended June 30, 2014 and 2013 and its cash flows for the six months ended June 30, 2014 and 2013. Such adjustments are of a normal and recurring nature. The results for the six months ended June 30, 2014 are not necessarily indicative of the results for the year ending December 31, 2014, or for any future period.
	On July 23, 2014, the Company completed the sale of 5,750,000 shares of its common stock in its initial public offering (the “IPO”), at a price to the public of $18.00 per share, resulting in net proceeds to the Company of $94.0 million after deducting underwriting discounts and commissions and estimated offering expenses payable by the Company. In preparation for the IPO, the Company’s board of directors and stockholders approved a 1-for-3.15 reverse stock split of the Company’s common stock effective July 2, 2014. All share and per share amounts in the unaudited financial statements contained herein and notes thereto have been retroactively adjusted, where necessary, to give effect to this reverse stock split. In connection with the closing of the IPO, all of the Company’s outstanding redeemable convertible preferred stock automatically converted into shares of common stock as of July 23, 2014, resulting in the issuance by the Company of an additional 18,007,575 shares of common stock. The significant increase in shares outstanding in July 2014 is expected to impact the year-over-year comparability of the Company’s net loss per share calculations over the next year.
Use of Estimates	'
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Fair Value Measurements	'
	Fair Value Measurements
	Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three categories:
	Level 1 -	Quoted market prices in active markets for identical assets or liabilities. At June 30, 2014 (unaudited) and December 31, 2013, the Company’s Level 1 assets consisted of a money market fund totaling $49,548 and $8,024, respectively.
	Level 2 -	Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. At June 30, 2014 (unaudited) and December 31, 2013, the Company had no Level 2 assets or liabilities.
	Level 3 -	Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. At June 30, 2014 (unaudited) and December 31, 2013, the Company had no Level 3 assets or liabilities.
	The Company’s financial instruments generally consist of cash equivalents, accounts payable and accrued expenses. The carrying amounts for the applicable financial instruments reported in the balance sheets approximate their fair values at June 30, 2014 (unaudited).
Deferred Offering Costs	'
	Deferred Offering Costs
	The Company capitalizes certain legal, accounting and other third-party fees that are directly associated with in-process equity financings as other assets until such financings are consummated. After consummation of the equity financing, these costs are recorded in stockholders’ equity (deficit) as a reduction of additional paid-in capital generated as a result of the offering. As of June 30, 2014 (unaudited), the Company recorded $1,640 of deferred offering costs, included in prepaid expenses and other current assets in the accompanying consolidated balance sheet, in contemplation of its July 2014 IPO. The Company did not record any deferred offering costs as of December 31, 2013.
Recently Issued Accounting Pronouncements	'
	Recently Issued Accounting Pronouncements
	In June 2014, the FASB issued guidance that removes all incremental reporting requirements for development stage entities, including the requirement to report inception-to-date information in the statements of income, cash flows, and shareholders' equity. These changes become effective for the Company on January 1, 2015 and early adoption is permitted. The Company elected to early adopt this guidance for the period ended June 30, 2014. The adoption of this guidance resulted in decreased financial statement disclosures, but did not impact the Company’s financial condition, results of operations or cash flows.
	There have been no other material changes to the significant accounting policies previously disclosed in the Company’s Prospectus.

Accrued_Expenses_Tables

Accrued Expenses (Tables)	6 Months Ended
	Jun. 30, 2014
Text Block [Abstract]	'
Schedule of Accrued Expenses	'
	Accrued expenses consist of the following:
		June 30, 2014		December 31, 2013
	Employee related expenses	$	674	$	49
	Development & Clinical Costs		686		57
	Professional services		210		190
	Initial public offering costs		474		—
	Other accrued expenses		25		31
	Total accrued expenses	$	2,069	$	327

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Summary of Recognized Stock-Based Compensation Expense	'
	The stock-based compensation expense recognized during the three and six months ended June 30, 2014 and 2013 was as follows:
		Three Months Ended June 30,						Six Months Ended June 30,
		2014			2013			2014		2013
	Stock compensation expense:
	Research and development	$	153		$	8		$	259	$	12
	General and administrative		182			—			236		—
		$	335		$	8		$	495	$	12
Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted	'
	The fair value of each option granted to employees and directors during the three and six months ended June 30, 2014 under the 2011 Stock Option Plan has been calculated on the date of grant using the following weighted average assumptions:
		Three Months Ended			Six Months Ended
		30-Jun-14			30-Jun-14
	Expected dividend yield		0	%		0	%
	Expected volatility		102.15	%		100.88
	Risk free interest rate		1.82	%		1.9	%
	Expected term		6.06 years			6.02 years
Summary of Activity Relating to Stock Options	'
	The table below summarizes activity related to stock options:
					Weighted-			Weighted-Average
					Average			Remaining Life (in		Aggregate Intrinsic
		Shares			Exercise Price			years)		Value
	Outstanding as of December 31, 2013		1,203,481		$	0.51			9.6	$	1,038
	Granted		680,940			6.77
	Exercised		(3,968	)		0.44
	Forfeited		(20,634	)		1.35
	Outstanding as of June 30, 2014		1,859,819		$	2.78			9.35	$	28,281
	Vested or expected to vest as of June 30, 2014		1,617,115		$	2.66			9.33	$	24,783
	Exercisable as of June 30, 2014		80,201		$	1.09			9.11	$	1,355
Summary of Activity Relating to Restricted Stock	'
	The table below summarizes activity relating to restricted stock:
					Weighted
					Average Grant
		Shares			Date Fair Value
	Unvested restricted common stock as of December 31, 2013		315,718		$	—
	Issued		—			—
	Vested		(71,647	)		—
	Forfeited		—			—
	Repurchased		(6,778	)		—
	Unvested restricted common stock as of June 30, 2014		237,293			—

Net_Loss_Per_Share_Tables

Net Loss Per Share (Tables)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share [Abstract]	'
Summary of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders	'
	The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders for the three and six months ended June 30, 2014 and 2013:
		Three Months Ended June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Numerator:
	Net loss attributable to common stockholders	$	(7,769	)	$	(4,655	)	$	(13,885	)	$	(8,044	)
	Denominator:
	Weighted average common shares outstanding—basic		1,700,517			1,464,419			1,676,864			1,442,774
	Dilutive effect of common share equivalents resulting from common share options and preferred common shares (as converted)		—			—			—			—
	Weighted average common shares outstanding—diluted		1,700,517			1,464,419			1,676,864			1,442,774
	Net loss per share attributable to common stockholders—basic and diluted	$	(4.57	)	$	(3.18	)	$	(8.28	)	$	(5.58	)
Summary of Common Stock Equivalents Presented on Weighted Average Basis	'
	The following common stock equivalents, presented on a weighted average basis, were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive:
		Three Months Ended June 30,						Six Months Ended June 30,
		2014			2013			2014			2013
	Options to purchase common stock		1,595,481			—			1,595,481			—
	Restricted stock		235,247			274,798			235,265			274,795
	Convertible preferred stock (as converted to common stock)		18,007,575			6,349,204			16,572,562			5,855,143
			19,838,303			6,624,002			18,403,308			6,129,938

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	6 Months Ended				0 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014	Dec. 31, 2013	Jul. 23, 2014	Jul. 02, 2014	Jul. 23, 2014	Jul. 23, 2014
			Money Market Fund [Member]	Money Market Fund [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]
			Level 1 [Member]	Level 1 [Member]			Initial Public Offering [Member]	Initial Public Offering [Member]
Summary Of Significant Accounting Policies [Line Items]	'	'	'	'	'	'	'	'
Initial public offering, common stock shares	'	'	'	'	'	'	5,750,000	'
Initial public offering, common stock price per share	'	'	'	'	'	'	'	$18
Net proceeds	'	'	'	'	'	'	$94,000,000	'
Reverse stock split description	'In preparation for the IPO, the Company's board of directors and stockholders approved a 1-for-3.15 reverse stock split of the Company's common stock	'	'	'	'	'	'	'
Reverse stock split effective date	2-Jul-14	'	'	'	'	'	'	'
Reverse stock split ratio	'	'	'	'	'	0.315	'	'
Issuance of additional shares of common stock upon conversion	'	'	'	'	18,007,575	'	'	'
Money market fund total	'	'	49,548,000	8,024,000	'	'	'	'
Deferred offering cots	$1,640,000	$0	'	'	'	'	'	'

Accrued_Expenses_Schedule_of_A

Accrued Expenses - Schedule of Accrued Expenses (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Payables And Accruals [Abstract]	'	'
Employee related expenses	$674	$49
Development & clinical costs	686	57
Professional services	210	190
Initial public offering costs	474	'
Other accrued expenses	25	31
Total accrued expenses	$2,069	$327

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)

3 Months Ended

6 Months Ended

3 Months Ended

6 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2014

Dec. 31, 2013

Jun. 30, 2014

Restricted Stock [Member]

Restricted Stock [Member]

Stock Options [Member]

Maximum [Member]

2011 Stock Option Plan [Member]

2011 Stock Option Plan [Member]

2011 Stock Option Plan [Member]

2011 Stock Option Plan [Member]

Restricted Stock [Member]

Maximum [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares authorized under the plan

'

'

'

'

'

'

'

'

'

'

'

3,142,857

Number of shares available for future issuance under the plan

'

'

'

'

'

'

'

'

648,952

648,952

'

'

Share based compensation granted under plan vest period

'

'

'

'

'

'

'

'

'

'4 years

'1 year

'

Share based compensation, cliff vesting percentage

'

'

'

'

'

'

'

'

'

25.00%

'

'

Share based compensation, vest period

'

'

'

'

'

'

'

'

'

'1 year

'

'

Share based compensation, term of plan

'

'

'

'

'

'

'

'

'

'10 years

'

'

Weighted average grant date fair value per share

'

'

'

'

'

'

'

'

$9.61

$8.90

'

'

Share option, forfeiture rate

10.00%

'

10.00%

'

'

'

'

'

'

'

'

'

Contractual term, option

'

'

'10 years

'

'

'

'

'

'

'

'

'

Unrecognized stock-based compensation expense

'

'

'

'

$239,000

$239,000

$4,953,000

'

'

'

'

'

Weighted average period of unrecognized compensation costs

'

'

'

'

'

'1 year 7 months 21 days

'3 years 4 months 10 days

'

'

'

'

'

Total fair value of shares vested

'

'

'

'

'

'

219,000

'

'

'

'

'

Proceeds from stock options exercised

'

'

'

'

'

'

2,000

'

'

'

'

'

Intrinsic value of options exercised

'

'

'

'

'

'

30,000

'

'

'

'

'

Stock-based compensation expense

335,000

8,000

495,000

12,000

33,000

55,000

'

'

'

'

'

'

Stock repurchased, shares

'

'

'

'

'

6,778

'

'

'

'

'

'

Stock repurchased, value

'

'

'

'

'

'

'

$1

'

'

'

'

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Recognized Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Total Stock-based compensation expense	$335	$8	$495	$12
Research and Development [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Total Stock-based compensation expense	153	8	259	12
General and Administrative [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Total Stock-based compensation expense	$182	'	$236	'

StockBased_Compensation_Summar1

Stock-Based Compensation - Summary of Weighted Average Assumptions Used to Compute Fair Value of Option Granted (Detail)	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2014
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'	'
Expected dividend yield	0.00%	0.00%
Expected volatility	102.15%	100.88%
Risk free interest rate	1.82%	1.90%
Expected term	'6 years 22 days	'6 years 7 days

StockBased_Compensation_Summar2

Stock-Based Compensation - Summary of Activity Relating to Stock Options (Detail) (Stock Options [Member], USD $)	6 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Stock Options [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Beginning balance, Shares--Stock options	1,203,481	'
Granted, Shares--Stock options	680,940	'
Exercised, Shares--Stock options	-3,968	'
Forfeited, Shares--Stock options	-20,634	'
Ending balance, Outstanding Shares--Stock options	1,859,819	1,203,481
Vested or expected to vest, Shares--Stock options	1,617,115	'
Exercisable, Shares--Stock options	80,201	'
Beginning balance, Weighted Average Exercise Price--Stock options	$0.51	'
Granted, Weighted Average Exercise Price--Stock options	$6.77	'
Exercised, Weighted Average Exercise Price--Stock options	$0.44	'
Forfeited, Weighted Average Exercise Price--Stock options	$1.35	'
Ending balance, Outstanding Weighted Average Exercise Price--Stock options	$2.78	$0.51
Vested or expected to vest, Weighted Average Exercise Price--Stock options	$2.66	'
Exercisable, Weighted Average Exercise Price--Stock options	$1.09	'
Outstanding, Weighted Average Remaining Life--Stock options	'9 years 4 months 6 days	'9 years 7 months 6 days
Vested or expected to vest, Weighted Average Remaining Life--Stock options	'9 years 3 months 29 days	'
Exercisable, Weighted Average Remaining Life--Stock options	'9 years 1 month 10 days	'
Outstanding, Aggregate Intrinsic Value--Stock options	$28,281	$1,038
Vested or expected to vest, Aggregate Intrinsic Value--Stock options	24,783	'
Exercisable, Aggregate Intrinsic Value--Stock options	$1,355	'

StockBased_Compensation_Summar3

Stock-Based Compensation - Summary of Activity Relating to Restricted Stock (Detail) (Restricted Stock [Member], USD $)	6 Months Ended
	Jun. 30, 2014
Restricted Stock [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Unvested restricted common stock, Shares at beginning balance--Restricted stock	315,718
Issued, Shares--Restricted stock	'
Vested, Shares--Restricted stock	-71,647
Forfeited, Shares--Restricted stock	'
Repurchased, Shares--Restricted stock	-6,778
Unvested restricted common stock, Shares at ending balance--Restricted stock	237,293
Unvested restricted common stock , Weighted Average Grant Date Fair Value Per Share, beginning balance--Restricted stock	'
Issued, Weighted Average Grant Date Fair Value Per Share--Restricted stock	'
Vested, Weighted Average Grant Date Fair Value Per Share--Restricted stock	'
Forfeited, Weighted Average Grant Date Fair Value Per Share--Restricted stock	'
Repurchased, Weighted Average Grant Date Fair Value Per Share--Restricted stock	'
Unvested restricted common stock, Weighted Average Grant Date Fair Value Per Share, ending balance--Restricted stock	'

Net_Loss_Per_Share_Schedule_of

Net Loss Per Share - Schedule of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Detail) (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Numerator:	'	'	'	'
Net loss attributable to common stockholders	($7,769)	($4,655)	($13,885)	($8,044)
Denominator:	'	'	'	'
Weighted average common shares outstanding - basic	1,700,517	1,464,419	1,676,864	1,442,774
Dilutive effect of common share equivalents resulting from common share options and preferred common shares (as converted)	'	'	'	'
Weighted average common shares outstanding - diluted	1,700,517	1,464,419	1,676,864	1,442,774
Net loss per share attributable to common stockholders - basic and diluted	($4.57)	($3.18)	($8.28)	($5.58)

Net_Loss_Per_Share_Summary_of_

Net Loss Per Share - Summary of Common Stock Equivalents Presented on Weighted Average Basis (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive common stock equivalents	19,838,303	6,624,002	18,403,308	6,129,938
Options to Purchase Common Stock [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive common stock equivalents	1,595,481	'	1,595,481	'
Restricted Stock [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive common stock equivalents	235,247	274,798	235,265	274,795
Convertible Preferred Stock (as Converted to Common Stock) [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Anti-dilutive common stock equivalents	18,007,575	6,349,204	16,572,562	5,855,143

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Income Tax Disclosure [Abstract]	'	'
State income tax benefit	$0	$0
Federal income tax benefit	$0	$0

Related_Party_Transactions_Add

Related Party Transactions - Additional Information (Detail) (Third Rock Ventures LLC [Member], USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Third Rock Ventures LLC [Member]	'	'	'	'
Related Party Transaction [Line Items]	'	'	'	'
Payment for consulting and management services	$99	$190	$224	$403
Accounts payable to related parties	$31	'	$31	'

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	6 Months Ended	0 Months Ended				0 Months Ended		0 Months Ended
In Millions, except Share data, unless otherwise specified	Jun. 30, 2014	Jul. 23, 2014	Jul. 02, 2014	Jul. 02, 2014	Jul. 02, 2014	Jul. 23, 2014	Jul. 23, 2014	Jul. 02, 2014
		Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]
				2014 Stock Option Plan [Member]	2014 Employee Stock Purchase Plan [Member]	Initial Public Offering [Member]	Initial Public Offering [Member]	Maximum [Member]
								2014 Stock Option Plan [Member]
Subsequent Event [Line Items]	'	'	'	'	'	'	'	'
Shares reserved for future issuance	'	'	'	1,143,000	'	'	'	'
Percentage of increase on issued and outstanding shares of Common stock	'	'	'	'	'	'	'	4.00%
Common stock authorized for issuance	'	'	'	'	282,000	'	'	'
Initial public offering, common stock shares	'	'	'	'	'	5,750,000	'	'
Initial public offering, common stock price per share	'	'	'	'	'	'	$18	'
Net proceeds	'	'	'	'	'	$94	'	'
Reverse stock split description	'In preparation for the IPO, the Company's board of directors and stockholders approved a 1-for-3.15 reverse stock split of the Company's common stock	'	'	'	'	'	'	'
Reverse stock split effective date	2-Jul-14	'	'	'	'	'	'	'
Reverse stock split ratio	'	'	0.315	'	'	'	'	'
Issuance of additional shares of common stock upon conversion	'	18,007,575	'	'	'	'	'	'