Aerie Pharmaceuticals (AERI) 10-K 27 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 20, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	AERI
Entity Registrant Name	AERIE PHARMACEUTICALS INC
Entity Central Index Key	1337553
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		24,046,939
Entity Public Float			$172,438

Balance_Sheets

Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets
Cash and cash equivalents	$85,586	$69,649
Short-term investments	54,339	0
Prepaid expenses and other current assets	1,122	618
Total current assets	141,047	70,267
Long-term investments	18,275	0
Furniture, fixtures and equipment, net	240	132
Other assets, net	1,523	59
Total assets	161,085	70,458
Current liabilities
Accounts payable and other current liabilities	8,336	3,482
Interest payable	551	0
Total current liabilities	8,887	3,482
Convertible notes, net of discounts	124,156	0
Total liabilities	133,043	3,482
Commitments and contingencies (Note 14)
Stockholders’ equity
Preferred stock, $0.001 par value; 15,000,000 shares authorized as of December 31, 2014 and December 31, 2013; None issued and outstanding	0	0
Common stock, $0.001 par value; 150,000,000 shares authorized as of December 31, 2014 and December 31, 2013; 24,018,577 and 23,285,549 shares issued and outstanding as of December 31, 2014 and December 31, 2013, respectively	24	23
Additional paid-in capital	171,326	162,021
Accumulated other comprehensive loss	-107	0
Accumulated deficit	-143,201	-95,068
Total stockholders’ equity	28,042	66,976
Total liabilities and stockholders’ equity	$161,085	$70,458

Balance_Sheets_Parenthetical

Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	15,000,000	15,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	24,018,577	23,285,549
Common stock, shares outstanding	24,018,577	23,285,549

Statements_of_Operations_and_C

Statements of Operations and Comprehensive Loss (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating expenses
General and administrative	($20,103)	($10,287)	($5,020)
Research and development	-29,869	-11,883	-9,273
Loss from operations	-49,972	-22,170	-14,293
Other income (expense), net	1,839	-8,978	-685
Net loss	-48,133	-31,148	-14,978
Net loss attributable to common stockholders—basic and diluted	-48,133	-31,598	-15,643
Net loss per share attributable to common stockholders—basic and diluted	($2)	($6.38)	($16.39)
Weighted average number of common shares outstanding—basic and diluted	24,086,651	4,955,760	954,695
Unrealized loss on available-for-sale investments	-107	0	0
Comprehensive loss	($48,240)	($31,148)	($14,978)

Statements_of_Stockholders_Equ

Statements of Stockholders' Equity (Deficit) (USD $)	Total	ADDITIONAL PAID-IN CAPITAL	ACCUMULATED OTHER COMPREHENSIVE LOSS	ACCUMULATED DEFICIT	COMMON STOCK	CONVERTIBLE PREFERRED STOCK
In Thousands, except Share data, unless otherwise specified
Beginning balance, value at Dec. 31, 2011	($48,697)	$109		($48,807)	$1	$60,348
Beginning balance, shares at Dec. 31, 2011					951,973	12,120,531
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, shares	12,907				12,907
Exercise of stock options, value	6	6
Stock-based compensation	430	430
Accretion from conversion of note payable to related parties	-292	-290		-2		292
Accretion of stock issuance costs	-258	-255		-3		258
Cash dividend	-130			-130
Conversion of convertible notes payable and accrued interest to common stock, value	0
Reclassification of warrants from liabilities to equity	0
Unrealized loss on available-for-sale investments	0
Net loss	-14,978			-14,978
Ending balance, value at Dec. 31, 2012	-63,919			-63,920	1	60,898
Ending balance, shares at Dec. 31, 2012					964,880	12,120,531
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, shares	3,195				3,195
Exercise of stock options, value	1	1
Vesting of restricted stock					124,966
Stock-based compensation	2,858	2,858
Accretion from conversion of note payable to related parties	-240	-240				240
Accretion of stock issuance costs	-210	-210				210
Issuance of convertible preferred stock for debt conversion, net of issuance costs, shares					12,120,531	-12,120,531
Issuance of convertible preferred stock for debt conversion, net of issuance costs, value	61,348	61,336			12	-61,348
Conversion of convertible notes payable and accrued interest to common stock, shares					1,860,363
Conversion of convertible notes payable and accrued interest to common stock, value	18,604	18,602			2
Issuance of common stock, shares					7,728,000
Issuance of common stock, value	68,226	68,218			8
Issuance of common stock upon net exercise of warrants, shares					483,614
Issuance of common stock upon net exercise of warrants, value	4,896	4,896
Reclassification of warrants from liabilities to equity	6,560	6,560
Unrealized loss on available-for-sale investments	0
Net loss	-31,148			-31,148
Ending balance, value at Dec. 31, 2013	66,976	162,021		-95,068	23
Ending balance, shares at Dec. 31, 2013					23,285,549
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options, shares	592,044				579,083
Exercise of stock options, value	9	8			1
Vesting of restricted stock					143,004
Stock-based compensation	9,178	9,178
Issuance of common stock upon exercise of stock purchase rights, shares					10,941
Issuance of common stock upon exercise of stock purchase rights, value	119	119
Accretion from conversion of note payable to related parties	0
Accretion of stock issuance costs	0
Conversion of convertible notes payable and accrued interest to common stock, value	0
Reclassification of warrants from liabilities to equity	0
Unrealized loss on available-for-sale investments	-107		-107
Net loss	-48,133			-48,133
Ending balance, value at Dec. 31, 2014	$28,042	$171,326	($107)	($143,201)	$24
Ending balance, shares at Dec. 31, 2014					24,018,577

Statements_of_Stockholders_Equ1

Statements of Stockholders' Equity (Deficit) (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
CONVERTIBLE PREFERRED STOCK
Underwriting discounts and commissions	$5,410
Offering costs	$3,644

Statements_of_Cash_Flows

Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Cash flows from operating activities
Net loss	($48,133)		($31,148)		($14,978)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation	73		64		138
Amortization and accretion costs related to notes payable—related parties	0		3,207		59
Amortization of deferred financing costs and debt discount	77		0		0
Amortization of discount on available-for-sale investments	416		0		0
Interest payable—related parties	0		588		16
Loss (gain) on conversion of notes payable	0		2,737		0
Stock-based compensation	9,178		2,858		430
Change in fair value measurements	0	[1]	3,717	[1]	630	[1]
Changes in operating assets and liabilities
Prepaid, current and other assets	-717		-516		9
Accounts payable and other current liabilities	4,829		2,045		-1,272
Interest payable	551		0		0
Net cash used in operating activities	-33,726		-16,448		-14,968
Cash flows from investing activities
Purchase of available-for-sale investments	-95,376		0		0
Maturity of available-for-sale investments	20,739		0		0
Sale of available-for-sale investments	1,500		0		0
Purchase of furniture, fixtures and equipment	-181		-63		-51
Net cash used in investing activities	-73,318		-63		-51
Cash flows from financing activities
Proceeds from issuance of convertible notes, net of discounts	124,150		0		0
Payments of debt issuance costs	-1,297		0		0
Proceeds from issuance of common stock in initial public offering, net of underwriting discounts	0		71,870		0
Payments of initial public offering costs	0		3,644		0
Proceeds from notes payable to related parties	0		15,000		3,000
Dividends paid	0		0		-130
Proceeds from exercise of stock options	9		1		6
Proceeds from exercise of warrants	0		8		0
Proceeds from exercise of stock purchase rights	119		0		0
Net cash provided by financing activities	122,981		83,235		2,876
Net change in cash and cash equivalents	15,937		66,724		-12,143
Cash and cash equivalents
Beginning of period	69,649		2,925		15,068
End of period	85,586		69,649		2,925
Supplemental disclosures
Interest paid	0		0		0
Non-cash financing activities
Conversion of preferred stock to common stock	0		61,348		0
Conversion of convertible notes payable and accrued interest to common stock	0		18,604		0
Issuance of common stock upon net exercise of warrants	0		4,888		0
Reclassification of warrants from liabilities to equity	0		6,560		0
Debt discount attributable to warrants	0		0		728
Accretion from conversion of note payable to related parties	0		240		292
Accretion of stock issuance costs	0		210		258
Deferred costs from issuance of convertible notes	$25		$0		$0
[1]	Includes change in fair value of warrant liabilities and change in fair value of a certain conversion feature related to the 2012 Notes (as defined herein) that was determined to be an embedded derivative requiring bifurcation and separate accounting. See Note 12 and Note 8, respectively.

The_Company

The Company	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company	The Company
	Aerie Pharmaceuticals, Inc. (the “Company”) is a clinical-stage pharmaceutical company focused on the discovery, development and commercialization of topical, small molecule drugs to treat patients with glaucoma and other diseases of the eye. Incorporated in the State of Delaware on June 22, 2005, the Company has its principal executive offices in Irvine, California. Clinical and finance operations are located in Bedminster, New Jersey and the Company conducts research in Research Triangle Park, North Carolina. Refer to Note 17 for further information regarding our Irvine, California office.
	The Company has not yet commenced primary operations or generated product revenue. The Company’s activities since inception primarily consisted of developing product candidates, raising capital and performing research and development activities. The Company has no current source of revenue to sustain its present activities, and it does not expect to generate revenue until and unless it receives regulatory approval of and successfully commercializes its product candidates. The Company has incurred losses and experienced negative operating cash flows since inception.
	The Company has funded its operations primarily through the sale of equity securities and issuance of convertible notes. In October 2013, the Company completed its initial public offering (“IPO”) and issued 7,728,000 shares of its common stock at an IPO price of $10.00 per share, including 1,008,000 shares of common stock issued upon the exercise in full by the underwriters of their option to purchase additional shares to cover over-allotments. The Company received net proceeds from the IPO of approximately $68.3 million, after deducting underwriting discounts and commissions of $5.4 million and expenses of $3.6 million. On September 30, 2014, the Company issued $125.0 million aggregate principal amount of senior secured convertible notes (the “2014 Convertible Notes”). The Company received net proceeds from the issuance of the 2014 Convertible Notes of approximately $124.1 million, after deducting discounts and certain expenses of $875,000. Refer to Note 8 for further information regarding the Convertible Notes.
	On November 3, 2014, the Company filed a shelf registration statement on Form S-3, which was declared effective by the SEC on November 10, 2014. The shelf registration statement permits: (i) the offering, issuance and sale of up to a maximum aggregate offering price of $150.0 million of the Company’s common stock; (ii) sales of common stock by certain selling stockholders; and (iii) the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $50.0 million of the Company’s common stock that may be issued and sold under an “at-the-market” sales agreement with Cantor Fitzgerald & Co. The common stock that may be offered, issued and sold by the Company under the “at-the-market” sales agreement is included in the $150.0 million of common stock that may be offered, issued and sold by us under the shelf registration statement. As of December 31, 2014, the Company has not sold any securities registered pursuant to the shelf registration statement.
	If the Company does not successfully commercialize any of its product candidates, it may be unable to generate product revenue or achieve profitability. Accordingly, the Company may be required to obtain further funding through other public or private offerings, debt financing, collaboration and licensing arrangements or other sources. Adequate additional funding may not be available to the Company on acceptable terms, or at all. If the Company is unable to raise capital when needed or on attractive terms, it would be forced to delay, reduce or eliminate its research and development programs or commercialization efforts.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies
	Basis of Presentation
	The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”).
	Use of Estimates
	The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of income and expenses during the reporting periods. Significant items subject to such estimates and assumptions include the valuation of stock options and warrants and operating expense accruals. Actual results could differ from those estimates.
	Segment Information
	Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating segment. All operations are located in the United States.
	Reverse Stock Split
	The Company effected a 1-for-5 reverse stock split on October 8, 2013. Accordingly, all share and per share amounts for all preceding periods presented in these financial statements and notes thereto, have been adjusted retroactively to reflect this reverse stock split, including reclassifying an amount equal to the reduction in par value to additional paid-in capital.
	Cash Equivalents
	Cash equivalents consist of short-term, highly liquid investments with an original term of three months or less at the date of purchase. Cash deposits are in six financial institutions in the United States.
	Concentration of Credit Risk
	The Company’s cash and cash equivalent balances with financial institutions exceed the $250,000 amount insured by the Federal Deposit Insurance Corporation.
	Deferred Financing Costs
	Deferred financing costs consist of financing costs incurred by the Company in connection with the closing of the Company’s 2014 Convertible Notes and are included in Other assets. The Company amortizes deferred financing costs through the earlier of maturity or the conversion of the 2014 Convertible Notes using the effective interest method. Refer to Note 8 for further information regarding the 2014 Convertible Notes.
	Debt Discounts
	Debt discounts consist of fees and expenses incurred by the Company in connection with the closing of the Company’s 2014 Convertible Notes that were paid directly to the note holders. The Company amortizes debt discounts through the earlier of maturity or the conversion of the 2014 Convertible Notes using the effective interest method. Refer to Note 8 for further information regarding the 2014 Convertible Notes.
	Furniture, Fixtures and Equipment, Net
	Furniture, fixtures and equipment is recorded at historical cost. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets. Repairs and maintenance are expensed when incurred. Upon retirement or sale, the cost of the assets disposed of and the related accumulated depreciation are removed from the accounts, and any resulting gain or loss is included in the determination of net income.
	Research and Development Costs
	Research and development costs are charged to expense as incurred and include, but are not limited to:
	•	Employee-related expenses including salaries, benefits, travel and stock-based compensation expense for research and development personnel;
	•	expenses incurred under agreements with contract research organizations, contract manufacturing organizations and service providers that assist in conducting clinical and preclinical studies;
	•	costs associated with preclinical activities and development activities;
	•	costs associated with regulatory operations; and
	•	depreciation expense for assets used in research and development activities.
	Costs for certain development activities, such as clinical studies, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations, or information provided to the Company by its vendors on their actual costs incurred. Payments for these activities are based on the terms of the individual arrangements, which may differ from the patterns of costs incurred, and are reflected in the financial statements as prepaid or accrued expense, which are reported in accounts payable and other current liabilities (Note 7). No material adjustments to these estimates have been recorded in these financial statements.
	Stock-Based Compensation
	Compensation cost of stock-based awards granted to employees is measured at grant date, based on the estimated fair value of the award. The Company estimates the fair value of stock options using a Black-Scholes option pricing model. Compensation expense for options granted to non-employees is determined as the fair value of consideration received or the fair value of the equity instruments issued, whichever is more reliably measured. The fair value of restricted stock awards is determined based on the fair value of the Company’s common stock on the date of grant. Stock-based compensation costs are expensed on a straight-line basis (net of estimated forfeitures) over the relevant vesting period. The fair value of unvested awards granted to non-employees is re-measured each period until the related service is complete. Compensation expense for employee stock purchase plan rights (“stock purchase rights”) is measured and recognized on the date that the Company becomes obligated to issue shares of common stock and is based on the difference between the fair value of the Company’s common stock and the purchase price on such date. All stock-based compensation costs are recorded between general and administrative and research and development costs in the statements of operations based upon the underlying employees roles within the Company. No related tax benefits of the stock-based compensation have been recognized.
	Investments
	The Company determines the appropriate classification of its investments in debt and equity securities at the time of purchase. The Company’s investments are comprised of certificates of deposit, commercial paper, corporate bonds and government agency securities that are classified as available-for-sale in accordance with ASC 320, Investments—Debt and Equity Securities. The Company classifies investments available to fund current operations as current assets on its balance sheet. Investments are classified as long-term assets on the balance sheet 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.
	Available-for-sale investments are recorded at fair value, with unrealized gains or losses included in Accumulated other comprehensive gain (loss) on the Company’s balance sheets. Realized gains and losses are determined using the specific identification method and are included as a component of Other income (expense), net (Note 3). There were no realized gains or losses recognized for the years ended December 31, 2014, 2013 or 2012.
	The Company reviews investments for other-than-temporary impairment whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. To determine whether an impairment is other-than-temporary, the Company considers its 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, the severity and the duration of the impairment and changes in value subsequent to period end. As of December 31, 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.
	Fair Value Measurements
	The Company records certain financial assets and liabilities at fair value based on the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants. The fair value of the Company’s financial instruments, including cash and cash equivalents, short-term investments, other current assets, accounts payable and accrued expenses approximate their respective carrying values due to the short-term nature of these instruments. The carrying amounts of long-term investments represent their estimated fair values. The estimated fair value of the Company’s 2014 Convertible Notes was $163.8 million as of December 31, 2014 (Note 5). As of December 31, 2014 and 2013, all outstanding warrants are classified as equity and are recorded within additional paid-in capital on the balance sheet (Note 12).
	Stock Purchase Warrants
	The Company accounts for its stock purchase warrants as either equity or liabilities based upon the characteristics and provisions of the underlying instruments. Warrants classified as equity are recorded as additional paid-in capital on the balance sheet and no further adjustments are made to their valuation. Warrants classified as liabilities are recorded at their fair value on the date of issuance and are re-measured on each subsequent balance sheet date until the earlier of the exercise or expiration of the applicable warrants or until such time that the warrants are no longer determined to be derivative instruments. The fair value changes are recognized as income (decreases in fair value) or expense (increases in fair value) in Other income (expense), net in the statements of operations and comprehensive loss. The fair value of these liabilities is estimated using the Black-Scholes method, which, under the Company’s facts and circumstances, approximates, in all material respects, the values determined when using a Monte Carlo simulation.
	Comprehensive Loss
	Comprehensive loss is comprised of net loss and other comprehensive loss. Other comprehensive loss includes changes in stockholders’ equity that are excluded from net income (loss), specifically changes in unrealized gains and losses on the Company’s available-for-sale securities.
	Income Taxes
	Deferred tax assets or liabilities are recorded for temporary differences between financial statement and tax basis of assets and liabilities, using enacted rates in effect for the year in which the differences are expected to reverse.
	Tax Valuation Allowance
	A valuation allowance is recorded if it is more likely than not that a deferred tax asset will not be realized. Due to the Company’s three year cumulative loss position, history of operating losses and losses expected to be incurred in the foreseeable future, a full valuation allowance was considered necessary. The Company has provided a full valuation allowance on its deferred tax assets that primarily consist of cumulative federal net operating losses of $133.6 million for the period from inception (June 22, 2005) to December 31, 2014 (Note 9).
	Recent Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board (the “FASB”) issued ASU 2014-15, which provides guidance about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. The new standard is effective for the Company for the annual period ending after December 15, 2016 and for annual and interim periods thereafter, with early adoption permitted. The Company is currently evaluating the impact of this accounting standard update on the Company’s financial statements.
	In June 2014, the FASB issued ASU 2014-10, which eliminates the concept of a development stage entity in its entirety from current accounting guidance. The new standard is effective for the Company for interim and annual periods beginning after December 15, 2014, with early adoption permitted. The Company evaluated and elected early adoption of ASU 2014-10 for the year ended December 31, 2014 and the Company no longer discloses inception-to-date information in its Statements of Operations and Comprehensive Loss, Cash Flows and Stockholders’ Equity (Deficit) and the related notes thereto.
	In July 2013, the FASB issued ASU 2013-11, which is an amendment to the accounting guidance on income taxes. This guidance provides clarification on the financial statement presentation of an unrecognized benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The amendment is effective for the Company for interim and annual periods beginning after December 15, 2013. The adoption of the provisions of this guidance did not have a material impact on the Company’s financial statements.
	In February 2013, the FASB issued ASU 2013-02 Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income, which requires that public and non-public companies present information about reclassification adjustments for accumulated other comprehensive income in their annual financial statements in a note or on the face of the financial statements. Public companies are also required to provide this information in interim financial statements. The new disclosure requirements are effective for fiscal years, and interim periods within those years, beginning after December 15, 2012. The adoption of the provisions of this guidance did not have a material impact on the Company’s results of operations, cash flows and financial position.
	Net Loss per Share Attributable to Common Stock
	Basic net loss per share attributable to common stock (“Basic EPS”) is calculated by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period, without consideration for potentially dilutive securities with the exception of warrants for common stock with a $0.05 exercise, which are exercisable for nominal consideration, and shares that are unequivocally issuable under the Company’s employee stock purchase plan and are therefore included in the calculation of the weighted-average number of shares of common stock as common stock equivalents. Net loss attributable to common stockholders is calculated by adjusting the Company’s net loss for accretion on convertible preferred stock, if any. Diluted net loss per share attributable to common stock (“Diluted EPS”) gives effect to all dilutive potential shares of common stock outstanding during this period. For Diluted EPS, net loss attributable to common stockholders used in calculating Basic EPS is adjusted for certain items related to the dilutive securities.
	For all periods presented, the Company’s potential common stock equivalents have been excluded from the computation of Diluted EPS as their inclusion would have the effect of reducing the net loss per share of common stock. Therefore, the denominator used to calculate Basic EPS and Diluted EPS is the same in all periods presented.
	The Company’s potential common stock equivalents that have been excluded from the computation of Diluted EPS for all periods presented consist of the following:
		DECEMBER 31,
		2014		2013		2012
	2014 convertible notes(1)	5,040,323		—		—
	Convertible preferred stock(2)	—		—		12,120,531
	Outstanding stock options	3,826,459		3,189,660		1,554,200
	Notes and interest payable to related parties(2)	$	—	$	—	$	3,016,000
	Stock purchase warrants	309,506		309,506		595,869
	Restricted common stock awards	103,064		246,068		—
	-1	Conversion is limited to a 9.985%ownership cap in shares of common stock by the holder. Additionally, the 2014 Convertible Notes provide for an increase in the conversion rate if conversion is elected in connection with a significant corporate transaction. Refer to Note 8 for further information regarding the 2014 Convertible Notes.
	-2	In connection with the completion of the Company’s IPO, the outstanding shares of convertible preferred stock and outstanding notes to related parties and accrued interest thereon were converted into 12,120,531 and 1,860,363 shares of common stock, respectively.

Other_Income_Expense_Net

Other Income (Expense), Net	12 Months Ended
	Dec. 31, 2014
Other Income and Expenses [Abstract]
Other Income (Expense), Net	Other Income (Expense), Net
	Other income (expense), net consist of the following:
		YEAR ENDED
		DECEMBER 31,
	(in thousands)	2014			2013			2012
	Interest and amortization expense	$	(628	)	$	(3,795	)	$	(75	)
	Loss on conversion of notes payable to related parties	—			(2,737		)	—
	Sale of New Jersey state tax benefit	2,288			1,268			—
	Expense due to change in fair value measurements(1)	—			(3,717		)	(630		)
	Other income, net	179			3			20
		$	1,839		$	(8,978	)	$	(685	)
	(1) Includes change in fair value of warrant liabilities and change in fair value of a certain conversion feature related to the 2012 Notes (as defined herein) that was determined to be an embedded derivative requiring bifurcation and separate accounting. See Note 12 and Note 8, respectively.

Investments

Investments	12 Months Ended
	Dec. 31, 2014
Cash and Cash Equivalents [Abstract]
Investments in Debt and Equity Instruments, Cash and Cash Equivalents, Unrealized and Realized Gains (Losses)	Investments
	Cash, cash equivalents and investments as of December 31, 2014 included the following:
				GROSS		GROSS
		AMORTIZED		UNREALIZED		UNREALIZED			FAIR
	(in thousands)	COST		GAINS		LOSSES			VALUE
	Cash and cash equivalents:
	Cash and money market accounts	$	84,613	$	—	$	—		$	84,613
	Certificates of deposit	472		—		—			472
	Corporate bonds	501		—		—			501
	Total cash and cash equivalents	$	85,586	$	—	$	—		$	85,586
	Investments:
	Certificates of deposit (due within 1 year)	$	25,823	$	—	$	(9	)	$	25,814
	Certificates of deposit (due within 2 years)	4,429		1		(3		)	4,427
	Commercial paper (due within 1 year)	5,988		1		(3		)	5,986
	Corporate bonds (due within 1 year)	16,487		—		(24		)	16,463
	Corporate bonds (due within 2 years)	13,912		—		(64		)	13,848
	Government agencies (due within 1 year)	6,082		—		(6		)	6,076
	Total investments	$	72,721	$	2	$	(109	)	$	72,614
	Total cash, cash equivalents, and investments	$	158,307	$	2	$	(109	)	$	158,200
	The Company held only cash and cash equivalents at December 31, 2013 and did not hold any investments.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements
	The Company records certain financial assets and liabilities at fair value in accordance with the provisions of ASC Topic 820 on fair value measurements. As defined in the guidance, fair value, defined as an exit price, represents the amount that would be received to sell an asset or pay to transfer a liability in an orderly transaction between market participants. As a result, fair value is a market-based approach that should be determined based on assumptions that market participants would use in pricing an asset or a liability. As a basis for considering these assumptions, the guidance defines a three-tier value hierarchy that prioritizes the inputs used in the valuation methodologies in measuring fair value.
	•	Level 1—Unadjusted quoted prices in active, accessible markets for identical assets or liabilities.
	•	Level 2—Other inputs that are directly or indirectly observable in the marketplace.
	•	Level 3—Unobservable inputs that are supported by little or no market activity.
	The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value.
	The following tables summarize the fair value of financial assets and liabilities that are measured at fair value and the classification by level of input within the fair value hierarchy:
			FAIR VALUE MEASUREMENTS AS OF
			DECEMEBER 31, 2014
	(in thousands)		LEVEL 1		LEVEL 2		LEVEL 3		TOTAL
	Cash and cash equivalents:
	Cash and money market accounts		$	84,613	$	—	$	—	$	84,613
	Certificates of deposit		—		472		—		472
	Corporate bonds		—		501		—		501
	Total cash and cash equivalents:		$	84,613	$	973	$	—	$	85,586
	Investments:
	Certificates of deposit		$	—	$	30,241	$	—	$	30,241
	Commercial paper		—		5,986		—		5,986
	Corporate bonds		—		30,311		—		30,311
	Government agencies		—		6,076		—		6,076
	Total investments		$	—	$	72,614	$	—	$	72,614
	Total cash, cash equivalents, and investments:		$	84,613	$	73,587	$	—	$	158,200
			FAIR VALUE MEASUREMENTS AS OF
			DECEMEBER 31, 2013
	(in thousands)		LEVEL 1		LEVEL 2		LEVEL 3		TOTAL
	Cash and cash equivalents:
	Cash and money market accounts		$	69,649	$	—	$	—	$	69,649
	Total cash and cash equivalents:		$	69,649	$	—	$	—	$	69,649
	As of December 31, 2014, the estimated fair value of the Company’s 2014 Convertible Notes was $163.8 million. The estimated fair value of the 2014 Convertible Notes was determined using a scenario analysis and Monte Carlo simulation model to capture the various features of the 2014 Convertible Notes. The scenario analysis and Monte Carlo simulation require the use of Level 3 unobservable inputs and subjective assumptions, including but not limited to the probability of conversion, stock price volatility, the risk free interest rate and credit spread. The estimates presented are not necessarily indicative of amounts that could be realized in a current market exchange. The use of alternative market assumptions and estimation methodologies could have a material effect on these estimates of fair value.
	The Company had no long-term debt as of December 31, 2013.

Furniture_Fixtures_and_Equipme

Furniture, Fixtures and Equipment, Net	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Furniture, Fixtures and Equipment, Net	Furniture, Fixtures and Equipment, Net
	Furniture, fixtures and equipment, net consist of the following:
		(in thousands)	ESTIMATED	DECEMBER 31,
			USEFUL LIVES
			(YEARS)	2014			2013
		Laboratory equipment	7	$	830		$	789
		Software and computer equipment	3	195			142
		Furniture and fixtures	5	238			151
				1,263			1,082
		Less: Accumulated depreciation		(1,023		)	(950		)
				$	240		$	132
	Depreciation expense was $73,000, $64,000 and $138,000 for years ended December 31, 2014, 2013 and 2012, respectively.

Accounts_Payable_Other_Current

Accounts Payable & Other Current Liabilities	12 Months Ended
	Dec. 31, 2014
Payables and Accruals [Abstract]
Accounts Payable & Other Current Liabilities	Accounts Payable & Other Current Liabilities
	Accounts payable and other current liabilities consist of the following:
		DECEMBER 31,
	(in thousands)	2014		2013
	Accounts payable	$	2,068	$	1,442
	Accrued expenses and other liabilities:
	Employee benefits and compensation related accruals(1)	2,257		966
	General and administrative related accruals	731		411
	Research and development related accruals	3,280		663
		$	8,336	$	3,482
	-1	Comprised of accrued bonus, accrued vacation, accrued severance liabilities, and liabilities under the Company’s employee stock purchase plan.

Convertible_Notes

Convertible Notes	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Convertible Notes	Convertible Notes
	On September 30, 2014, the Company issued the 2014 Convertible Notes to Deerfield Partners, L.P., Deerfield International Master Fund, L.P., Deerfield Private Design Fund III, L.P., Deerfield Special Situations Fund, L.P. and Deerfield Special Situations International Master Fund, L.P. (collectively, “Deerfield”).
	The 2014 Convertible Notes bear interest at a rate of 1.75% per annum payable quarterly in arrears on the first business day of each January, April, July and October, commencing on January 1, 2015. The 2014 Convertible Notes mature on the seventh anniversary from the date of issuance, unless earlier converted.
	The 2014 Convertible Notes constitute a senior secured obligation of the Company, collateralized by a first priority security interest in substantially all of the assets of the Company. The 2014 Convertible Notes provide that, upon the request of the Company, Deerfield will release all of the liens on the collateral if both of the following occur: (i) beginning one month after U.S. Food and Drug Administration approval of either RhopressaTM or RoclatanTM, shares of the Company’s common stock have traded at a price above $30 per share (subject to adjustment for any subdivision or combination of outstanding common stock) for 30 consecutive trading days, and (ii) the Company is prepared to close a financing that will be secured by a lien on the Company’s assets, subject only to the release of the lien on the Company’s assets by Deerfield.
	At closing, the Company paid Deerfield a one-time transaction fee of $625,000. In addition, the Company reimbursed Deerfield in the amount of $250,000 for certain expenses incurred by Deerfield in connection with the transaction. The Company also incurred $1.3 million of legal and advisory fees in connection with the transaction.
	The 2014 Convertible Notes are convertible at any time at the option of Deerfield, in whole or in part, into shares of common stock, including upon the repayment of the 2014 Convertible Notes at maturity (the “Conversion Option”). However, upon conversion, Deerfield (together with their affiliates) is limited to a 9.985% ownership cap in shares of common stock (the “9.985% Cap”). The 9.985% Cap would remain in place upon any assignment of the 2014 Convertible Notes by Deerfield.
	The initial conversion price is $24.80 per share of common stock (equivalent to an initial conversion rate of 40.32 shares of common stock per $1,000 principal amount of 2014 Convertible Notes), representing a 30% premium over the closing price of the common stock on September 8, 2014. The conversion rate and the corresponding conversion price are subject to adjustment for stock dividends (other than a dividend for which Deerfield would be entitled to participate on an as-converted basis), stock splits, reverse stock splits and reclassifications. In addition, in connection with certain significant corporate transactions, Deerfield, at its option, may (i) require the Company to prepay all or a portion of the principal amount of the 2014 Convertible Notes, plus accrued and unpaid interest, or (ii) convert all or a portion of the principal amount of the 2014 Convertible Notes into, depending upon the type of transaction, shares of common stock or the right to receive upon consummation of the transaction the consideration Deerfield would have received had Deerfield converted the 2014 Convertible Notes immediately prior to the consummation of the transaction. The 2014 Convertible Notes provide for an increase in the conversion rate if Deerfield elects to convert their 2014 Convertible Notes in connection with a significant corporate transaction. The maximum increase to the initial conversion rate, in connection with a significant corporate transaction, is 12.07 shares of common stock per $1,000 principal amount of 2014 Conversion Notes, which decreases over time and is determined by reference to the price of the common stock prior to the consummation of the significant corporate transaction or the value of the significant corporate transaction.
	The agreement governing the 2014 Convertible Notes contains various representations and warranties, and affirmative and negative covenants, customary for financings of this type, including restrictions on the incurrence of additional debt and liens on the Company’s assets. As of December 31, 2014, the Company was in compliance with these convenants. The agreement governing the 2014 Convertible Notes also provides for certain events of default, including the failure to pay principal and interest when due; inaccuracies in the Company’s representations and warranties to Deerfield; failure to comply with any of the covenants; the Company’s insolvency or the occurrence of certain bankruptcy-related events; certain judgments against the Company; the suspension, cancellation or revocation of governmental authorizations that are reasonably expected to have a material adverse effect on the Company’s business; the acceleration of a specified amount of indebtedness; and the failure to deliver shares of common stock upon conversion of the 2014 Convertible Notes. If any event of default were to occur, and continue beyond any applicable cure period, the holders of more than 50% of the aggregate principal amount of the then outstanding 2014 Convertible Notes would be permitted to declare the principal and accrued and unpaid interest to be immediately due and payable.
	The Company recorded the 2014 Convertible Notes as long-term debt at face value less debt discounts relating to fees and certain expenses paid to Deerfield in connection with the transaction. The Conversion Option is a derivative that qualifies for an exemption from bifurcation and liability accounting as provided for in ASC Topic 815 “Derivatives and Hedging – Contracts in Entity’s Own Equity” (“ASC 815”). Since the Conversion Option is not bifurcated as a derivative pursuant to ASC 815, the Company further evaluated the Conversion Option to determine whether it is considered a beneficial conversion feature (“BCF”). The Company determined that the initial accounting conversion price was greater than the fair value of the common stock at the close of trading on the date of issuance, therefore no BCF existed at inception. However, if Deerfield elects to convert their 2014 Convertible Notes in connection with a significant corporate transaction, the increase to the initial conversion rate may cause a contingent BCF to exist at the time of conversion. The contingent BCF, if any, will be recognized in earnings when the contingency is resolved and will be measured using the fair value of the common stock at the close of trading on the date of issuance and the accounting conversion price as adjusted for such an increase to the initial conversion rate.
	As of September 30, 2014, the Company recognized unamortized debt discounts of $875,000. Debt discounts are amortized using the effective interest method through the earlier of maturity or the conversion of the 2014 Convertible Notes.
	The table below summarizes the carrying value of the 2014 Convertible Notes as of December 31, 2014:
	(in thousands)	31-Dec-14
	Gross proceeds	$	125,000
	Initial value of issuance costs recorded as debt discount	(875		)
	Amortization of debt discount	31
	Carrying value	$	124,156
	For the year ended December 31, 2014, interest expense related to the 2014 Convertible Notes was $551,000.
	On December 7, 2012, the Company authorized the sale of convertible notes (the “2012 Notes”) to related parties in the aggregate principal amount of $15.0 million. The 2012 Notes accrued interest at a rate of 8% per annum, with principal plus accrued interest thereon due upon maturity at September 30, 2013. The initial closing comprised of five individual convertible notes with an aggregate principal balance of $3.0 million. As of December 31, 2012, $12.0 million of 2012 Notes were authorized and available for sale. On March 28, 2013, May 23, 2013 and August 9, 2013, the Company completed the second, third and fourth closing of the 2012 Notes, respectively. The closings each comprised of five individual convertible notes with aggregate principal balances of $3.0 million, $4.5 million, and $4.5 million, respectively. On August 9, 2013, the Company amended the agreements relating to the 2012 Notes. The amendment authorized the sale of an additional $3.0 million of the 2012 Notes, resulting in an aggregate principal amount of $18.0 million being authorized. In addition, the amendment extended the maturity date of the 2012 Notes from September 30, 2013 to December 31, 2013 and the issuance period through November 30, 2013. No other terms and conditions of the agreements were changed as part of the amendment. In accordance with ASC 470 Debt, the amendment met the criteria of a troubled debt restructuring and the amortization of the debt discount was revised to align with a new effective interest rate determined as of the amendment date. No gain was recorded as part of the restructuring. On September 30, 2013, the Company completed the fifth closing of the 2012 Notes. Aggregate proceeds to the Company were $3.0 million.
	On October 30, 2013, upon closing of the IPO, the principal and accrued interest outstanding under the 2012 Notes were converted into 1,860,363 shares of common stock at a conversion price equal to the IPO price of $10.00 per share. The Company accounted for the conversion as an extinguishment of debt.
	In connection with the issuance of the 2012 Notes, the Company determined that a certain conversion feature was an embedded derivative requiring bifurcation and separate accounting. To estimate the fair value, the Company compared the net present value of expected cash flows of the issued 2012 Notes with and without the conversion feature comprising the embedded derivative. The Company determined that the fair value of the embedded derivative was immaterial as of August 9, 2013, May 23, 2013, March 28, 2013 and December 7, 2012, representing the fourth, third, second and initial closing dates, and as of December 31, 2012. As of September 30, 2013, the fair value of the embedded derivative was $96,000 . The Company determined that upon the closing of the IPO on October 30, 2013, at which time the 2012 Notes were converted into common stock, no embedded derivative existed. The Company recorded the change in fair value as a component of Other income (expense), net.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	No provision for U.S. federal or state income taxes has been recorded as the Company has incurred net operating losses since inception. Significant components of the Company’s net deferred income tax assets as of December 31, 2014 and 2013 consist of the following:
		DECEMBER 31,
	(in thousands)	2014				2013
	Net deferred tax assets:
	Tax loss carry-forwards	$	42,863			$	35,428
	Other assets	4,882				1,742
	Research and development credits	631				556
	Other liabilities	(693		)		(782		)
	Valuation allowance	(47,683		)		(36,944		)
	Total net deferred income taxes	$	—			$	—
	A reconciliation of the statutory tax rates and the effective tax rates for the years ended December 31, 2014, 2013 and 2012 is as follows:
		YEAR ENDED DECEMBER 31,
		2014			2013			2012
	U.S. federal tax rate	35	%		35	%		35	%
	State tax rate	6.13	%		5.36	%		5.17	%
	Other	(0.04	)%		(0.03	)%		(0.02	)%
	Valuation allowance	(41.09	)%		(40.33	)%		(40.15	)%
	Effective tax rate	—	%		—	%		—	%
	Realization of the future tax benefits is dependent on the Company’s ability to generate sufficient taxable income within the carry-forward period. Due to the Company’s history of operating losses, the deferred tax assets arising from the aforementioned future tax benefits are currently not likely to be realized and, accordingly, are offset by a full valuation allowance. The income tax provision varies from the expected provision determined by applying the federal statutory income tax rate to income (loss). The reasons for the difference in the expected provision, as determined by applying the federal statutory income tax rate to net income (loss) is primarily due to the increase in the deferred income tax valuation allowance of $10.7 million, $11.1 million and $6.1 million for the years ended December 31, 2014, 2013 and 2012, respectively. The net increase in the deferred income tax valuation allowance of $10.7 million for the year ended December 31, 2014, reflects a reduction of $2.5 million attributable to the transfer of deferred state tax benefits to an unrelated third party as permitted by the New Jersey Economic Development Authority’s sponsored Technology Business Tax Certificate Transfer Program.
	As of December 31, 2014, the Company has federal and state net operating loss carry-forwards of approximately $133.6 million and $136.6 million, respectively, and federal research and development tax credit carry-forwards of $0.6 million available to offset federal and state income tax, which expire from 2024 through 2032. Included in the net operating loss carry-forwards are approximately $8.3 million of net operating loss carry-forwards related to exercises of Non-qualified Stock Options, the tax benefit from which, if realized, will be credited to additional paid-in capital. Utilization of the net operating loss carry-forwards and credits may be subject to a substantial annual limitation due to the ownership change limitations provided by the Internal Revenue Code of 1986, as amended, or the IRC, and similar state provisions. The effect of an ownership change could be an imposition of an annual limitation on the use of net operating loss carry-forwards attributable to periods before the change.

Convertible_Preferred_Stock

Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Convertible Preferred Stock	Convertible Preferred Stock
	On October 30, 2013, immediately prior to the closing of the Company’s IPO, all outstanding shares of convertible preferred stock automatically were converted into an aggregate 12,120,531 shares of common stock. As of December 31, 2014 and December 31, 2013, the Company does not have any convertible preferred stock authorized, issued or outstanding.
	On February 23, 2011, the Company received $23.8 million in proceeds from the issuance of its Series B Convertible Preferred Stock, net of $1.2 million of transaction costs.
	In connection with the issuance of the 2012 Notes, the Company’s certificate of incorporation was amended on December 7, 2012, to authorize the issuance of 16,534,582 shares of preferred stock, of which 400,000 were designated as Series A-1 Preferred Stock; 2,002,006 were designated as Series A-2 Preferred Stock; 4,495,895 were designated as Series A-3 Preferred Stock; 1,136,681 were designated as Series A-4 Preferred Stock; and 8,500,000 were designated as Series B Preferred Stock.
	Carrying Value
	The convertible preferred stock was originally recorded at the net proceeds received by the Company at issuance. The difference between the net proceeds and the total redemption price was being accreted on a straight-line basis over the period from issuance until the earliest redemption date and was accreted to the convertible preferred stock capital account through the completion of the IPO. Accretion amounted to $210,000, and $258,000 for the years ended December 31, 2013 and 2012, respectively.
	The Series A-4 Convertible Preferred Stock issued in connection with the conversion of the 2010 Notes on February 23, 2011 was recorded at fair value. The difference between stated and fair value of $1.3 million was being accreted on a straight-line basis of the period from February 23, 2011 until the earliest redemption date and was accreted to the Series A-4 Convertible Preferred Stock capital account through the completion of the IPO. Accretion amounted to $240,000 and $292,000 for the years ended December 31, 2013 and 2012, respectively. The Company determined that the straight-line method approximated the effective interest method.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity
	On October 30, 2013, the Company completed its IPO and issued 7,728,000 shares of its common stock at an IPO price of $10.00 per share, including 1,008,000 shares of common stock issued upon the exercise in full by the underwriters of their option to purchase additional shares to cover over-allotments. The shares began trading on the NASDAQ Global Market on October 25, 2013. The Company received net proceeds from the IPO of approximately $68.3 million, after deducting underwriting discounts and commissions of $5.4 million and expenses of $3.6 million.
	In connection with the IPO, the following events occurred:
	•	On October 24, 2013, 297,366 warrants to purchase convertible preferred stock were net exercised and were subsequently automatically converted into 297,366 shares of common stock on October 30, 2013 (Note 12);
	•	On October 30, 2013, 186,248 warrants to purchase convertible preferred stock were net exercised and were subsequently automatically converted into 186,248 shares of common stock on October 30, 2013 (Note 12);
	•	On October 30, 2013, the outstanding shares of convertible preferred stock were automatically converted into an aggregate 12,120,531 shares of common stock (Note 10);
	•	On October 30, 2013, 717,801 warrants to purchase convertible preferred stock were automatically converted into 717,801 warrants to purchase common stock, at which time the liabilities were re-measured and reclassified to equity (Note 12);
	•	On October 30, 2013, the principal and interest outstanding under the Company’s 2012 Notes were converted into 1,860,363 shares of common stock at a conversion price equal to the IPO price of $10.00 per share (Note 8);
	•	On October 30, 2013, the 2013 Omnibus Incentive Plan became effective under which 3,229,068 equity awards for common stock of the Company may be distributed (Note 13); and
	•	On October 30, 2013, the 2013 Employee Stock Purchase Plan became effective under which a maximum of 645,814 shares of common stock of the Company may be issued (Note 16).
	Additionally, on October 30, 2013, the Company’s certificate of incorporation was amended to increase the number of authorized shares of common stock to 150,000,000 with a par value of $0.001 per share and decrease the number of authorized preferred stock to 15,000,000 with a par value of $0.001 per share.
	On November 3, 2014, the Company filed a shelf registration statement on Form S-3, which was declared effective by the SEC on November 10, 2014. The shelf registration statement permits: (i) the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $150.0 million of the Company’s common stock; (ii) sales of common stock by certain selling stockholders; and (iii) the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $50.0 million of the Company’s common stock that may be issued and sold under an “at-the-market” sales agreement with Cantor Fitzgerald & Co. The common stock that may be offered, issued and sold by the Company under the “at-the-market” sales agreement is included in the $150.0 million of common stock that may be offered, issued and sold by the Company under the shelf registration statement. As of December 31, 2014, the Company has not sold any securities registered pursuant to the shelf registration statement.
	Holders of common stock are entitled to dividends when and if declared by the Company’s Board of Directors subject to prior rights of the holders of any preferred stock. The holder of each share of common stock is entitled to one vote.

Stock_Purchase_Warrants

Stock Purchase Warrants	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Stock Purchase Warrants	Stock Purchase Warrants
	During 2006, in connection with a long-term debt agreement, the Company granted warrants to purchase 2,006 shares of Series A-2 Convertible Preferred Stock. The term of the warrants extends ten years from the grant date and the warrants are exercisable at any time during that ten-year period.
	In connection with the convertible notes issued in 2012, 2010 and 2009, the Company sold warrants to purchase 1,275,680 shares of Series B, Series A-4 or Series A-3 Convertible Preferred Stock as of December 31, 2013. The term of the warrants issued in 2010 and 2009 extends ten years from the grant date. The term of the warrants issued in 2012 extends seven years from the grant date. All warrants were issued with certain provisions that protect holders from a decline in stock price.
	On October 24, 2013, warrants to purchase 297,366 shares of Series B and Series A-3 Convertible Preferred Stock were net exercised and were subsequently automatically converted into 297,366 shares of common stock on October 30, 2013. On October 30, 2013, warrants to purchase 186,248 shares of Series B, Series A-4 and Series A-3 Convertible Preferred Stock were net exercised and were subsequently automatically converted into 186,248 shares of common stock on October 30, 2013.
	On October 30, 2013, upon closing of the IPO, the remaining 717,801 outstanding warrants to purchase convertible preferred stock were automatically converted into 717,801 warrants to purchase common stock and all price protection provisions associated with the warrants were removed, at which time the liabilities were revalued and reclassified to equity.
	As of December 31, 2014, the following warrants were outstanding:
	NUMBER OF		EXERCISE				WARRANT	TYPE OF EQUITY
	UNDERLYING		PRICE PER				EXPIRATION	SECURITY
	SHARES		SHARE				DATE
	2,006		$	5			Mar-16	Common Stock
	75,000		$	5			Feb-19	Common Stock
	75,000		$	5			Nov-19	Common Stock
	157,500		$	5			Aug-20	Common Stock
	408,295		$	0.05			Dec-19	Common Stock
	The warrants outstanding at December 31, 2014 are all currently exercisable with weighted-average remaining lives of 4.99 years.
	Prior to the IPO, the Company recognized all of its outstanding warrants as liabilities on its balance sheet as they were subject to price protection provisions. The liability was revalued at each reporting period and changes in the fair value of the warrant liability were included as a component of Other income (expense), net. The initial recognition and subsequent changes in fair value of the warrant liability had no effect on the Company’s cash flows.
	The Company estimated the fair value of the warrants using the Black-Scholes option-pricing model utilizing the fair value of underlying preferred and common stock. Black-Scholes has inherent limitations for use in the case of a warrant with a price protection provision, since the model is designed to be used when the inputs to the model are static throughout the life of a security. Management concluded, under the Company’s facts and circumstances, that the estimated fair values of the warrants using the Black-Scholes option-pricing model approximates, in all material respects, the values determined using a Monte Carlo valuation model. The estimates in the Black-Scholes option-pricing model and the Monte Carlo valuation model are based, in part, on assumptions, including but not limited to stock price volatility, the expected life of the warrants, the risk free rate and the fair value of the equity stock underlying the warrants.
	Key assumptions utilized in the fair value calculation as of October 30, 2013, the IPO closing date, and December 31, 2012 appear in the table below.
		OCTOBER 30, 2013			DECEMBER 31, 2012
	Expected term (years)	5.32-6.84			6.13-7.66
	Volatility	65	%		60	%
	Risk-free interest rate	1.51%-2.00%			0.98%-1.31%
	Dividend yield	—	%		—	%

Stockbased_Compensation

Stock-based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based Compensation	Stock-based Compensation
	Stock-based compensation expense for options granted, restricted stock, and stock purchase rights are reflected in the statement of operations as follows:
		YEAR ENDED DECEMBER 31,
	(in thousands)	2014			2013				2012
	Research and development	$	1,339		$	222			$	89
	General and administrative	7,839			2,636				341
	Total	$	9,178		$	2,858			$	430
	Stock Option Plan
	The Company maintains two equity compensation plans, the 2005 Aerie Pharmaceutical Stock Plan (the “2005 Plan”) and the 2013 Omnibus Incentive Plan (the “2013 Equity Plan”). The 2005 Plan and the 2013 Plan are referred to collectively as the “Plans.” On July 13, 2005, the Company’s Board of Directors adopted and approved the 2005 Plan, which, as amended in 2008, 2009, 2011 and 2013, provides for the granting of up to 3,586,277 stock-based awards to employees, directors and consultants of the Company. The Board of Directors determines price, term and vesting conditions of all stock-based awards at their grant date. Absent a public market price for the Company’s common stock prior to completion of the IPO, the Board of Directors determined the estimated fair market value for the underlying common stock based on their appraisal of the Company’s fair value. Stock-based awards vest over variable periods, generally ranging from one to five years, and expire not more than ten years after the date of grant. On October 30, 2013, the effective date of the 2013 Equity Plan, the 2005 Plan was frozen and no additional awards will be made under the 2005 Plan. Any shares remaining available for future grant under the 2005 Plan were allocated to the 2013 Equity Plan. The 2013 Equity Plan provides for the granting of up to 3,229,068 equity awards for common stock of the Company. As of December 31, 2014, 1,263,100 equity awards have been granted under the 2013 Equity Plan.
	The following table summarizes the stock option activity under the Plans:
		NUMBER OF		WEIGHTED AVERAGE
		SHARES		EXERCISE PRICE
	Options outstanding at December 31, 2011	1,152,194		$	0.31
	Granted	575,200		1.45
	Exercised	(12,907	)	0.39
	Cancelled	(160,287	)	0.23
	Options outstanding at December 31, 2012	1,554,200		$	1.39
	Granted	2,009,551		3.11
	Exercised	(3,195	)	0.37
	Cancelled	(370,896	)	1.38
	Options outstanding at December 31, 2013	3,189,660		$	2.16
	Granted	1,263,100		20.38
	Exercised	(592,044	)	0.42
	Cancelled	(34,257	)	14.32
	Options outstanding at December 31, 2014	3,826,459		$	8.39
	Options exercisable at December 31, 2014	1,329,347		$	2.18
	The aggregate intrinsic value of options exercised for the years ended December 31, 2014, 2013 and 2012 was $10.5 million, $9,000 and $10,000, respectively. Intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for which the options were exercised.
	The following table provides additional information about the Company’s stock options that are outstanding and exercisable at December 31, 2014:
	EXERCISE		OPTIONS		WEIGHTED				AGGREGATE		WEIGHTED	OPTIONS	WEIGHTED		AGGREGATE
	PRICE		OUTSTANDING		AVERAGE				INTRINSIC		AVERAGE	EXERCISABLE	AVERAGE		INTRINSIC
					EXERCISE				VALUE		REMAINING		EXERCISE		VALUE
					PRICE						CONTRACTUAL		PRICE
											LIFE (YEARS)
									(000’s)						(000’s)
	$0.01 - $3.15		2,591,459								8	1,327,012
	15.55 - 17.97		180,500								9.3	—
	19.07 - 22.31		969,700								9.2	2,335
	24.59 - 25.99		84,800								9.7	—
			3,826,459		$	8.34			$	79,792		1,329,347	$	2.18	$	35,911
	As of December 31, 2014, the Company had $23.1 million of unrecognized compensation expense related to unvested share options granted under the Plans. This cost is expected to be recognized over a weighted average period of 2.6 years as of December 31, 2014. The weighted average remaining contractual life on all outstanding options as of December 31, 2014 was 8.4 years.
	The intrinsic value is calculated as the difference between the estimated fair market value and the exercise price per share of the stock options. The estimated fair market value per share of common stock as of December 31, 2014 and 2013 was $29.19 and $17.96, respectively.
	The estimated fair value of options granted is determined on the date of grant using the Black-Scholes option pricing model. Options granted to non-employees are revalued at each financial reporting period until required service is performed.
	Key assumptions utilized in the fair value calculation for the underlying common stock as of December 31, 2014 and December 31, 2013 and 2012 appear on the table below.
		YEAR ENDED
		DECEMBER 31,
		2014		2013			2012
	Expected term (years)	6.25		6.25			6.25
	Expected stock price volatility(1)	80.44	%	79.2	%		60	%
	Risk-free interest rate	1.9	%	1.78	%		1.05	%
	Dividend yield	—	%	—	%		—	%
	(1) Weighted Average for 2014
	The Company utilized the guidance set forth in the SEC Staff Accounting Bulletin 107, Share-Based Payment (“SAB 107”), to determine the expected term of options. The Company utilized the simplified method as prescribed by SAB 107, as it does not have sufficient historical exercise and post vesting termination data to provide a reasonable basis upon which to estimate the expected term of stock options granted to employees. The risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected time to liquidity.
	Volatility is based on historical volatility of several public entities that are similar to the Company as the Company does not have sufficient historical transactions of its own shares on which to base expected volatility. This peer group of companies utilized in 2014 remained consistent with that of 2013. Other than a one-time dividend in October 2012 related to the spin-off of certain non-core intellectual property rights (Note 15), the Company has not historically issued any dividends and does not expect to in the foreseeable future.
	Restricted Common Stock
	On March 21, 2013, concurrent with the cancellation of 345,000 stock options, the Company issued 371,034 shares of restricted stock to an employee. The vesting of these awards is time-based with terms of two to four years. These restricted stock awards are subject to repurchase, such that the Company has the right, but not the obligation, to repurchase unvested shares upon the employee’s termination. As of December 31, 2014, 103,064 shares of restricted stock awards were unvested and subject to repurchase.
	Compensation expense related to these restricted stock awards is based on the market value of the Company’s common stock on the date of grant and is expensed on a straight-line basis (net of estimated forfeitures) over the vesting period. The weighted average remaining contractual term for restricted stock awards as of December 31, 2014 was 1.4 years. Compensation expense related to restricted stock awards for the years ended December 31, 2014 and 2013 was $390,000 and $346,000, respectively and was included in general and administrative expense. As of December 31, 2014, the Company had $242,000 of unrecognized compensation expense, related to unvested restricted stock awards. This cost is expected to be recognized over a weighted average period of 1.4 years as of December 31, 2014.
	Stock Purchase Rights
	On October 30, 2013, the Company’s 2013 Employee Stock Purchase Plan (the “Purchase Plan”) became effective (Note 16). Compensation expense for stock purchase rights under the Purchase Plan is measured and recognized on the date that the Company becomes obligated to issue shares of common stock and is based on the difference between the fair value of the Company’s common stock and the purchase price on such date. Compensation expense related to stock purchase rights for the years ended December 31, 2014 and 2013 was $63,000 and $66,000, respectively.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Lease Commitment Summary
	The following table presents future minimum commitments of the Company due under non-cancelable operating leases with original or remaining terms in excess of one year at December 31, 2014.
	Minimum lease payments were as follows at December 31, 2014:
	(in thousands)
	2015	$	460
	2016	309
	2017	332
	2018	328
	2019	396
	2020 and thereafter	267
	Total minimum lease payments	$	2,092
	Rent expense was $579,000, $403,000 and $333,000 for the years ended December 31, 2014, 2013 and 2012, respectively, and is reflected in general and administrative expenses and research and development expenses as determined by the underlying activities occurring at each of the Company’s locations.
	Litigation
	The Company is not party to any known litigation, is not aware of any unasserted claims and does not have contingency reserves established for any litigation liabilities.
	Contract Service Providers
	In the course of the Company’s normal business operations, it has agreements with contract service providers to assist in the performance of its research and development, clinical research and manufacturing. Substantially all of these contracts are on an as needed basis.

RelatedParty_Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related-Party Transactions	Related-Party Transactions
	Prior to their conversion into common stock in connection with the IPO (Note 8), the 2012 Notes were due to holders of the Company’s convertible preferred stock. Interest expense on those obligations for the years ended December 31, 2013 and 2012 was $588,000 and $16,000, respectively.
	In October 2012, the Company formed Novaer Holding, Inc. (“Novaer”), a wholly-owned entity, and contributed certain non-core, non-competitive intellectual property, including an exclusive license for Aerie’s intellectual property for non-ophthalmic indications, and $0.1 million in cash for initial funding. The Board of Directors declared a dividend and distributed 100% of Novaer’s equity interests to Aerie’s stockholders and warrant holders of record as of September 6, 2012. The book value of the non-core intellectual property was $0. The cash included in the transaction was recorded as a $0.1 million cash dividend. Following this spin-off, Novaer is an independent company. Aerie does not own an equity interest and has no significant influence by contract or other means. In addition, Aerie does not retain any rights or obligations and has no share in profits or earnings. On September 6, 2013, the Company terminated its agreement to exclusively license to Novaer its intellectual property for non-ophthalmic indications. No consideration, or future obligation thereof, was exchanged in connection with this termination. As of December 31, 2014, the Company owns all of the worldwide rights to its current product candidates for all indications, both ophthalmic and non-ophthalmic.
	For the years ended December 31, 2014, 2013 and 2012, the respective amounts of approximately $333,000, $190,000 and $34,000 were paid to board members, some of whom served as consultants of the Company through consulting agreements containing arm’s-length terms typical of agreements entered into with unaffiliated third parties.

Benefit_Plan

Benefit Plan	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Benefit Plan	Benefit Plan
	401 (k) Plan
	The Company has adopted a 401(k) deferred compensation plan. Eligible employees meeting the participant criteria may contribute up to the statutory limitation ($17,500 for each of 2014 and 2013). The Company may contribute a discretionary match if it elects to do so. During the years ended December 31, 2014, 2013 and 2012, the Company contributed $0 as a matching contribution to the plan.
	Employee Stock Purchase Plan
	On October 30, 2013, the Company adopted the Purchase Plan under which substantially all employees may purchase the Company’s common stock through payroll deductions and lump sum contributions at a price equal to 85% of the lower of the fair market values of the stock as of the beginning or the end of the offering periods. Employees may not purchase more than $25,000 of stock during any calendar year. As of December 31, 2014, approximately 634,873 shares were reserved for future issuance under the Purchase Plan.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events
	In January 2015, the Company participated in the New Jersey Economic Development Authority’s sponsored Technology Business Tax Certificate Transfer Program to transfer $3.1 million in state tax benefits to unrelated profitable businesses with operations in the state of New Jersey. The Company received net proceeds of $2.9 million from the transfer.
	In January 2015, the Company entered into a lease agreement (the “Irvine Lease Agreement”) under which the Company is leasing approximately 14,500 square feet of office space in Irvine, California. The initial term of the lease expires in January 2021. Total additional rental payments under the Irvine Lease Agreement are approximately $2.9 million and are expected to be incurred from January 2015 to January 2021.
	On February 25, 2015, the Board of Directors authorized grants of common stock options and restricted stock awards to the officers of the Company in the aggregate amount of 363,750 and 60,627, respectively. The options have an exercise price of $28.03 per share, a term of four years and are subject to vesting conditions over a four-year period. The aggregate fair value of these option grants was $6.7 million. The restricted stock awards are subject to vesting conditions over a four-year period. The aggregate fair value of these restricted stock awards was $1.7 million.

Selected_Quarterly_Financial_D

Selected Quarterly Financial Data	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data	18.    Selected Quarterly Financial Data (Unaudited)
	The following table presents selected unaudited quarterly financial information for the years ended December 31, 2014 and 2013. The results for any quarter are not necessarily indicative of future quarterly results and, accordingly, period to period comparisons should not be relied upon as an indication of future performance.
		FOR THE QUARTER ENDED
	(in thousands, except share and per share amounts)	DECEMBER 31,			SEPTEMBER 30,			JUNE 30,			MARCH 31,
	Year Ended December 31, 2014
	Operating expenses	$	(15,973	)	$	(13,174	)	$	(11,843	)	$	(8,982	)
	Net loss attributable to common stockholders	$	(16,501	)	$	(13,147	)	$	(11,814	)	$	(6,671	)
	Net loss per share attributable to common stockholders—basic and diluted	$	(0.69	)	$	(0.54	)	$	(0.49	)	$	(0.28	)
		DECEMBER 31,			SEPTEMBER 30,			JUNE 30,			MARCH 31,
	Year Ended December 31, 2013
	Operating expenses	$	(6,750	)	$	(5,686	)	$	(5,113	)	$	(4,621	)
	Net loss attributable to common stockholders	$	(10,319	)	$	(10,887	)	$	(6,465	)	$	(3,927	)
	Net loss per share attributable to common stockholders—basic and diluted	$	(0.62	)	$	(10.81	)	$	(6.59	)	$	(4.07	)

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”).
Use of Estimates	Use of Estimates
	The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and reported amounts of income and expenses during the reporting periods. Significant items subject to such estimates and assumptions include the valuation of stock options and warrants and operating expense accruals. Actual results could differ from those estimates.
Segment Information	Segment Information
	Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one operating segment. All operations are located in the United States.
Reverse Stock Split	Reverse Stock Split
	The Company effected a 1-for-5 reverse stock split on October 8, 2013. Accordingly, all share and per share amounts for all preceding periods presented in these financial statements and notes thereto, have been adjusted retroactively to reflect this reverse stock split, including reclassifying an amount equal to the reduction in par value to additional paid-in capital.
Cash Equivalents	Cash Equivalents
	Cash equivalents consist of short-term, highly liquid investments with an original term of three months or less at the date of purchase. Cash deposits are in six financial institutions in the United States.
Concentration of Credit Risk	Concentration of Credit Risk
	The Company’s cash and cash equivalent balances with financial institutions exceed the $250,000 amount insured by the Federal Deposit Insurance Corporation
Deferred Financing Costs	Deferred Financing Costs
	Deferred financing costs consist of financing costs incurred by the Company in connection with the closing of the Company’s 2014 Convertible Notes and are included in Other assets. The Company amortizes deferred financing costs through the earlier of maturity or the conversion of the 2014 Convertible Notes using the effective interest method. Refer to Note 8 for further information regarding the 2014 Convertible Notes.
Debt Discount	Debt Discounts
	Debt discounts consist of fees and expenses incurred by the Company in connection with the closing of the Company’s 2014 Convertible Notes that were paid directly to the note holders. The Company amortizes debt discounts through the earlier of maturity or the conversion of the 2014 Convertible Notes using the effective interest method. Refer to Note 8 for further information regarding the 2014 Convertible Notes.
Furniture, Fixtures and Equipment, Net	Furniture, Fixtures and Equipment, Net
	Furniture, fixtures and equipment is recorded at historical cost. Depreciation is calculated using the straight-line method over the estimated useful lives of the related assets. Repairs and maintenance are expensed when incurred. Upon retirement or sale, the cost of the assets disposed of and the related accumulated depreciation are removed from the accounts, and any resulting gain or loss is included in the determination of net income.
Research and Development Costs	Research and Development Costs
	Research and development costs are charged to expense as incurred and include, but are not limited to:
	•	Employee-related expenses including salaries, benefits, travel and stock-based compensation expense for research and development personnel;
	•	expenses incurred under agreements with contract research organizations, contract manufacturing organizations and service providers that assist in conducting clinical and preclinical studies;
	•	costs associated with preclinical activities and development activities;
	•	costs associated with regulatory operations; and
	•	depreciation expense for assets used in research and development activities.
	Costs for certain development activities, such as clinical studies, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations, or information provided to the Company by its vendors on their actual costs incurred. Payments for these activities are based on the terms of the individual arrangements, which may differ from the patterns of costs incurred, and are reflected in the financial statements as prepaid or accrued expense, which are reported in accounts payable and other current liabilities (Note 7). No material adjustments to these estimates have been recorded in these financial statements.
Stock-Based Compensation	Stock-Based Compensation
	Compensation cost of stock-based awards granted to employees is measured at grant date, based on the estimated fair value of the award. The Company estimates the fair value of stock options using a Black-Scholes option pricing model. Compensation expense for options granted to non-employees is determined as the fair value of consideration received or the fair value of the equity instruments issued, whichever is more reliably measured. The fair value of restricted stock awards is determined based on the fair value of the Company’s common stock on the date of grant. Stock-based compensation costs are expensed on a straight-line basis (net of estimated forfeitures) over the relevant vesting period. The fair value of unvested awards granted to non-employees is re-measured each period until the related service is complete. Compensation expense for employee stock purchase plan rights (“stock purchase rights”) is measured and recognized on the date that the Company becomes obligated to issue shares of common stock and is based on the difference between the fair value of the Company’s common stock and the purchase price on such date. All stock-based compensation costs are recorded between general and administrative and research and development costs in the statements of operations based upon the underlying employees roles within the Company. No related tax benefits of the stock-based compensation have been recognized.
Investment	Investments
	The Company determines the appropriate classification of its investments in debt and equity securities at the time of purchase. The Company’s investments are comprised of certificates of deposit, commercial paper, corporate bonds and government agency securities that are classified as available-for-sale in accordance with ASC 320, Investments—Debt and Equity Securities. The Company classifies investments available to fund current operations as current assets on its balance sheet. Investments are classified as long-term assets on the balance sheet 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.
	Available-for-sale investments are recorded at fair value, with unrealized gains or losses included in Accumulated other comprehensive gain (loss) on the Company’s balance sheets. Realized gains and losses are determined using the specific identification method and are included as a component of Other income (expense), net (Note 3). There were no realized gains or losses recognized for the years ended December 31, 2014, 2013 or 2012.
	The Company reviews investments for other-than-temporary impairment whenever the fair value of an investment is less than the amortized cost and evidence indicates that an investment’s carrying amount is not recoverable within a reasonable period of time. To determine whether an impairment is other-than-temporary, the Company considers its 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, the severity and the duration of the impairment and changes in value subsequent to period end. As of December 31, 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.
Fair Value Measurements	Fair Value Measurements
	The Company records certain financial assets and liabilities at fair value based on the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants. The fair value of the Company’s financial instruments, including cash and cash equivalents, short-term investments, other current assets, accounts payable and accrued expenses approximate their respective carrying values due to the short-term nature of these instruments. The carrying amounts of long-term investments represent their estimated fair values. The estimated fair value of the Company’s 2014 Convertible Notes was $163.8 million as of December 31, 2014 (Note 5). As of December 31, 2014 and 2013, all outstanding warrants are classified as equity and are recorded within additional paid-in capital on the balance sheet (Note 12).
Stock Purchase Warrants	Stock Purchase Warrants
	The Company accounts for its stock purchase warrants as either equity or liabilities based upon the characteristics and provisions of the underlying instruments. Warrants classified as equity are recorded as additional paid-in capital on the balance sheet and no further adjustments are made to their valuation. Warrants classified as liabilities are recorded at their fair value on the date of issuance and are re-measured on each subsequent balance sheet date until the earlier of the exercise or expiration of the applicable warrants or until such time that the warrants are no longer determined to be derivative instruments. The fair value changes are recognized as income (decreases in fair value) or expense (increases in fair value) in Other income (expense), net in the statements of operations and comprehensive loss. The fair value of these liabilities is estimated using the Black-Scholes method, which, under the Company’s facts and circumstances, approximates, in all material respects, the values determined when using a Monte Carlo simulation.
Comprehensive Loss	Comprehensive Loss
	Comprehensive loss is comprised of net loss and other comprehensive loss. Other comprehensive loss includes changes in stockholders’ equity that are excluded from net income (loss), specifically changes in unrealized gains and losses on the Company’s available-for-sale securities.
Income Taxes	Income Taxes
	Deferred tax assets or liabilities are recorded for temporary differences between financial statement and tax basis of assets and liabilities, using enacted rates in effect for the year in which the differences are expected to reverse.
Tax Valuation Allowance	Tax Valuation Allowance
	A valuation allowance is recorded if it is more likely than not that a deferred tax asset will not be realized. Due to the Company’s three year cumulative loss position, history of operating losses and losses expected to be incurred in the foreseeable future, a full valuation allowance was considered necessary. The Company has provided a full valuation allowance on its deferred tax assets that primarily consist of cumulative federal net operating losses of $133.6 million for the period from inception (June 22, 2005) to December 31, 2014 (Note 9).
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board (the “FASB”) issued ASU 2014-15, which provides guidance about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. The new standard is effective for the Company for the annual period ending after December 15, 2016 and for annual and interim periods thereafter, with early adoption permitted. The Company is currently evaluating the impact of this accounting standard update on the Company’s financial statements.
	In June 2014, the FASB issued ASU 2014-10, which eliminates the concept of a development stage entity in its entirety from current accounting guidance. The new standard is effective for the Company for interim and annual periods beginning after December 15, 2014, with early adoption permitted. The Company evaluated and elected early adoption of ASU 2014-10 for the year ended December 31, 2014 and the Company no longer discloses inception-to-date information in its Statements of Operations and Comprehensive Loss, Cash Flows and Stockholders’ Equity (Deficit) and the related notes thereto.
	In July 2013, the FASB issued ASU 2013-11, which is an amendment to the accounting guidance on income taxes. This guidance provides clarification on the financial statement presentation of an unrecognized benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. The amendment is effective for the Company for interim and annual periods beginning after December 15, 2013. The adoption of the provisions of this guidance did not have a material impact on the Company’s financial statements.
	In February 2013, the FASB issued ASU 2013-02 Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income, which requires that public and non-public companies present information about reclassification adjustments for accumulated other comprehensive income in their annual financial statements in a note or on the face of the financial statements. Public companies are also required to provide this information in interim financial statements. The new disclosure requirements are effective for fiscal years, and interim periods within those years, beginning after December 15, 2012. The adoption of the provisions of this guidance did not have a material impact on the Company’s results of operations, cash flows and financial position.
Net Loss per Share Attributable to Common Stock	Net Loss per Share Attributable to Common Stock
	Basic net loss per share attributable to common stock (“Basic EPS”) is calculated by dividing the net loss attributable to common stockholders by the weighted average number of shares of common stock outstanding for the period, without consideration for potentially dilutive securities with the exception of warrants for common stock with a $0.05 exercise, which are exercisable for nominal consideration, and shares that are unequivocally issuable under the Company’s employee stock purchase plan and are therefore included in the calculation of the weighted-average number of shares of common stock as common stock equivalents. Net loss attributable to common stockholders is calculated by adjusting the Company’s net loss for accretion on convertible preferred stock, if any. Diluted net loss per share attributable to common stock (“Diluted EPS”) gives effect to all dilutive potential shares of common stock outstanding during this period. For Diluted EPS, net loss attributable to common stockholders used in calculating Basic EPS is adjusted for certain items related to the dilutive securities.
	For all periods presented, the Company’s potential common stock equivalents have been excluded from the computation of Diluted EPS as their inclusion would have the effect of reducing the net loss per share of common stock. Therefore, the denominator used to calculate Basic EPS and Diluted EPS is the same in all periods presented.
	The Company’s potential common stock equivalents that have been excluded from the computation of Diluted EPS for all periods presented consist of the following:
		DECEMBER 31,
		2014		2013		2012
	2014 convertible notes(1)	5,040,323		—		—
	Convertible preferred stock(2)	—		—		12,120,531
	Outstanding stock options	3,826,459		3,189,660		1,554,200
	Notes and interest payable to related parties(2)	$	—	$	—	$	3,016,000
	Stock purchase warrants	309,506		309,506		595,869
	Restricted common stock awards	103,064		246,068		—
	-1	Conversion is limited to a 9.985%ownership cap in shares of common stock by the holder. Additionally, the 2014 Convertible Notes provide for an increase in the conversion rate if conversion is elected in connection with a significant corporate transaction. Refer to Note 8 for further information regarding the 2014 Convertible Notes.
	-2	In connection with the completion of the Company’s IPO, the outstanding shares of convertible preferred stock and outstanding notes to related parties and accrued interest thereon were converted into 12,120,531 and 1,860,363 shares of common stock, respectively.

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Schedule of Computation of Diluted EPS	The Company’s potential common stock equivalents that have been excluded from the computation of Diluted EPS for all periods presented consist of the following:
		DECEMBER 31,
		2014		2013		2012
	2014 convertible notes(1)	5,040,323		—		—
	Convertible preferred stock(2)	—		—		12,120,531
	Outstanding stock options	3,826,459		3,189,660		1,554,200
	Notes and interest payable to related parties(2)	$	—	$	—	$	3,016,000
	Stock purchase warrants	309,506		309,506		595,869
	Restricted common stock awards	103,064		246,068		—

Other_Income_Expense_Net_Table

Other Income (Expense), Net (Tables)	12 Months Ended
	Dec. 31, 2014
Other Income and Expenses [Abstract]
Schedule of Other Income (Expense), Net	Other income (expense), net consist of the following:
		YEAR ENDED
		DECEMBER 31,
	(in thousands)	2014			2013			2012
	Interest and amortization expense	$	(628	)	$	(3,795	)	$	(75	)
	Loss on conversion of notes payable to related parties	—			(2,737		)	—
	Sale of New Jersey state tax benefit	2,288			1,268			—
	Expense due to change in fair value measurements(1)	—			(3,717		)	(630		)
	Other income, net	179			3			20
		$	1,839		$	(8,978	)	$	(685	)
	(1) Includes change in fair value of warrant liabilities and change in fair value of a certain conversion feature related to the 2012 Notes (as defined herein) that was determined to be an embedded derivative requiring bifurcation and separate accounting. See Note 12 and Note 8, respectively.

Investments_Tables

Investments (Tables)	12 Months Ended
	Dec. 31, 2014
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Investments	Cash, cash equivalents and investments as of December 31, 2014 included the following:
				GROSS		GROSS
		AMORTIZED		UNREALIZED		UNREALIZED			FAIR
	(in thousands)	COST		GAINS		LOSSES			VALUE
	Cash and cash equivalents:
	Cash and money market accounts	$	84,613	$	—	$	—		$	84,613
	Certificates of deposit	472		—		—			472
	Corporate bonds	501		—		—			501
	Total cash and cash equivalents	$	85,586	$	—	$	—		$	85,586
	Investments:
	Certificates of deposit (due within 1 year)	$	25,823	$	—	$	(9	)	$	25,814
	Certificates of deposit (due within 2 years)	4,429		1		(3		)	4,427
	Commercial paper (due within 1 year)	5,988		1		(3		)	5,986
	Corporate bonds (due within 1 year)	16,487		—		(24		)	16,463
	Corporate bonds (due within 2 years)	13,912		—		(64		)	13,848
	Government agencies (due within 1 year)	6,082		—		(6		)	6,076
	Total investments	$	72,721	$	2	$	(109	)	$	72,614
	Total cash, cash equivalents, and investments	$	158,307	$	2	$	(109	)	$	158,200

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	The following tables summarize the fair value of financial assets and liabilities that are measured at fair value and the classification by level of input within the fair value hierarchy:
		FAIR VALUE MEASUREMENTS AS OF
		DECEMEBER 31, 2014
	(in thousands)	LEVEL 1		LEVEL 2		LEVEL 3		TOTAL
	Cash and cash equivalents:
	Cash and money market accounts	$	84,613	$	—	$	—	$	84,613
	Certificates of deposit	—		472		—		472
	Corporate bonds	—		501		—		501
	Total cash and cash equivalents:	$	84,613	$	973	$	—	$	85,586
	Investments:
	Certificates of deposit	$	—	$	30,241	$	—	$	30,241
	Commercial paper	—		5,986		—		5,986
	Corporate bonds	—		30,311		—		30,311
	Government agencies	—		6,076		—		6,076
	Total investments	$	—	$	72,614	$	—	$	72,614
	Total cash, cash equivalents, and investments:	$	84,613	$	73,587	$	—	$	158,200
		FAIR VALUE MEASUREMENTS AS OF
		DECEMEBER 31, 2013
	(in thousands)	LEVEL 1		LEVEL 2		LEVEL 3		TOTAL
	Cash and cash equivalents:
	Cash and money market accounts	$	69,649	$	—	$	—	$	69,649
	Total cash and cash equivalents:	$	69,649	$	—	$	—	$	69,649

Furniture_Fixtures_and_Equipme1

Furniture, Fixtures and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Furniture, Fixtures and Equipment, Net	Furniture, fixtures and equipment, net consist of the following:
		(in thousands)	ESTIMATED	DECEMBER 31,
			USEFUL LIVES
			(YEARS)	2014			2013
		Laboratory equipment	7	$	830		$	789
		Software and computer equipment	3	195			142
		Furniture and fixtures	5	238			151
				1,263			1,082
		Less: Accumulated depreciation		(1,023		)	(950		)
				$	240		$	132

Accounts_Payable_Other_Current1

Accounts Payable & Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Payables and Accruals [Abstract]
Summary of Accounts Payable and Other Current Liabilities	Accounts payable and other current liabilities consist of the following:
		DECEMBER 31,
	(in thousands)	2014		2013
	Accounts payable	$	2,068	$	1,442
	Accrued expenses and other liabilities:
	Employee benefits and compensation related accruals(1)	2,257		966
	General and administrative related accruals	731		411
	Research and development related accruals	3,280		663
		$	8,336	$	3,482
	-1	Comprised of accrued bonus, accrued vacation, accrued severance liabilities, and liabilities under the Company’s employee stock purchase plan.

Convertible_Notes_Convertible_

Convertible Notes Convertible Notes (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Convertible Debt	The table below summarizes the carrying value of the 2014 Convertible Notes as of December 31, 2014:
	(in thousands)	31-Dec-14
	Gross proceeds	$	125,000
	Initial value of issuance costs recorded as debt discount	(875		)
	Amortization of debt discount	31
	Carrying value	$	124,156

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Summary of Significant Components of Company's Net Deferred Income Tax Assets	Significant components of the Company’s net deferred income tax assets as of December 31, 2014 and 2013 consist of the following:
		DECEMBER 31,
	(in thousands)	2014				2013
	Net deferred tax assets:
	Tax loss carry-forwards	$	42,863			$	35,428
	Other assets	4,882				1,742
	Research and development credits	631				556
	Other liabilities	(693		)		(782		)
	Valuation allowance	(47,683		)		(36,944		)
	Total net deferred income taxes	$	—			$	—
Reconciliation of U.S. Statutory Rate and Effective Tax Rate	A reconciliation of the statutory tax rates and the effective tax rates for the years ended December 31, 2014, 2013 and 2012 is as follows:
		YEAR ENDED DECEMBER 31,
		2014			2013			2012
	U.S. federal tax rate	35	%		35	%		35	%
	State tax rate	6.13	%		5.36	%		5.17	%
	Other	(0.04	)%		(0.03	)%		(0.02	)%
	Valuation allowance	(41.09	)%		(40.33	)%		(40.15	)%
	Effective tax rate	—	%		—	%		—	%

Stock_Purchase_Warrants_Tables

Stock Purchase Warrants (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Schedule of Warrants Outstanding	As of December 31, 2014, the following warrants were outstanding:
	NUMBER OF		EXERCISE				WARRANT	TYPE OF EQUITY
	UNDERLYING		PRICE PER				EXPIRATION	SECURITY
	SHARES		SHARE				DATE
	2,006		$	5			Mar-16	Common Stock
	75,000		$	5			Feb-19	Common Stock
	75,000		$	5			Nov-19	Common Stock
	157,500		$	5			Aug-20	Common Stock
	408,295		$	0.05			Dec-19	Common Stock
Schedule of Key Assumptions Utilized in Fair Value Calculation	Key assumptions utilized in the fair value calculation as of October 30, 2013, the IPO closing date, and December 31, 2012 appear in the table below.
		OCTOBER 30, 2013			DECEMBER 31, 2012
	Expected term (years)	5.32-6.84			6.13-7.66
	Volatility	65	%		60	%
	Risk-free interest rate	1.51%-2.00%			0.98%-1.31%
	Dividend yield	—	%		—	%

Stockbased_Compensation_Tables

Stock-based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Expense for Options Granted and Restricted Stock as Reflected in the Statement of Operations	Stock-based compensation expense for options granted, restricted stock, and stock purchase rights are reflected in the statement of operations as follows:
		YEAR ENDED DECEMBER 31,
	(in thousands)	2014			2013				2012
	Research and development	$	1,339		$	222			$	89
	General and administrative	7,839			2,636				341
	Total	$	9,178		$	2,858			$	430
Schedule of Stock Options Activity	The following table summarizes the stock option activity under the Plans:
		NUMBER OF		WEIGHTED AVERAGE
		SHARES		EXERCISE PRICE
	Options outstanding at December 31, 2011	1,152,194		$	0.31
	Granted	575,200		1.45
	Exercised	(12,907	)	0.39
	Cancelled	(160,287	)	0.23
	Options outstanding at December 31, 2012	1,554,200		$	1.39
	Granted	2,009,551		3.11
	Exercised	(3,195	)	0.37
	Cancelled	(370,896	)	1.38
	Options outstanding at December 31, 2013	3,189,660		$	2.16
	Granted	1,263,100		20.38
	Exercised	(592,044	)	0.42
	Cancelled	(34,257	)	14.32
	Options outstanding at December 31, 2014	3,826,459		$	8.39
	Options exercisable at December 31, 2014	1,329,347		$	2.18
Schedule of Stock Options Outstanding and Exercisable Option Plans	The following table provides additional information about the Company’s stock options that are outstanding and exercisable at December 31, 2014:
	EXERCISE		OPTIONS		WEIGHTED				AGGREGATE		WEIGHTED	OPTIONS	WEIGHTED		AGGREGATE
	PRICE		OUTSTANDING		AVERAGE				INTRINSIC		AVERAGE	EXERCISABLE	AVERAGE		INTRINSIC
					EXERCISE				VALUE		REMAINING		EXERCISE		VALUE
					PRICE						CONTRACTUAL		PRICE
											LIFE (YEARS)
									(000’s)						(000’s)
	$0.01 - $3.15		2,591,459								8	1,327,012
	15.55 - 17.97		180,500								9.3	—
	19.07 - 22.31		969,700								9.2	2,335
	24.59 - 25.99		84,800								9.7	—
			3,826,459		$	8.34			$	79,792		1,329,347	$	2.18	$	35,911
Schedule of Key Assumptions Utilized in Fair Value Calculation	Key assumptions utilized in the fair value calculation for the underlying common stock as of December 31, 2014 and December 31, 2013 and 2012 appear on the table below.
		YEAR ENDED
		DECEMBER 31,
		2014		2013			2012
	Expected term (years)	6.25		6.25			6.25
	Expected stock price volatility(1)	80.44	%	79.2	%		60	%
	Risk-free interest rate	1.9	%	1.78	%		1.05	%
	Dividend yield	—	%	—	%		—	%

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Summary of Future Minimum Lease Payments	Minimum lease payments were as follows at December 31, 2014:
	(in thousands)
	2015	$	460
	2016	309
	2017	332
	2018	328
	2019	396
	2020 and thereafter	267
	Total minimum lease payments	$	2,092

Selected_Quarterly_Financial_D1

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Financial Information	Selected Quarterly Financial Data (Unaudited)
	The following table presents selected unaudited quarterly financial information for the years ended December 31, 2014 and 2013. The results for any quarter are not necessarily indicative of future quarterly results and, accordingly, period to period comparisons should not be relied upon as an indication of future performance.
		FOR THE QUARTER ENDED
	(in thousands, except share and per share amounts)	DECEMBER 31,			SEPTEMBER 30,			JUNE 30,			MARCH 31,
	Year Ended December 31, 2014
	Operating expenses	$	(15,973	)	$	(13,174	)	$	(11,843	)	$	(8,982	)
	Net loss attributable to common stockholders	$	(16,501	)	$	(13,147	)	$	(11,814	)	$	(6,671	)
	Net loss per share attributable to common stockholders—basic and diluted	$	(0.69	)	$	(0.54	)	$	(0.49	)	$	(0.28	)
		DECEMBER 31,			SEPTEMBER 30,			JUNE 30,			MARCH 31,
	Year Ended December 31, 2013
	Operating expenses	$	(6,750	)	$	(5,686	)	$	(5,113	)	$	(4,621	)
	Net loss attributable to common stockholders	$	(10,319	)	$	(10,887	)	$	(6,465	)	$	(3,927	)
	Net loss per share attributable to common stockholders—basic and diluted	$	(0.62	)	$	(10.81	)	$	(6.59	)	$	(4.07	)

The_Company_Details

The Company (Details) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended
	Oct. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Nov. 10, 2014
Organization And Nature Of Business [Line Items]
Common stock initial public offering	7,728,000
Public offering price of the shares sold	$10
Net proceeds from initial public offering	$68,300,000	$0	$71,870,000	$0
Underwriting discounts and commissions	5,410,000
Payments of initial public offering costs	3,644,000	0	3,644,000	0
Proceeds from issuance of convertible notes, net of discounts		124,150,000	0	0
Stock offering underwriter overallotment option
Organization And Nature Of Business [Line Items]
Common stock initial public offering	1,008,000
Convertible debt
Organization And Nature Of Business [Line Items]
Convertible notes, net of discounts		125,000,000
Proceeds from issuance of convertible notes, net of discounts		124,100,000
Convertible notes payable
Organization And Nature Of Business [Line Items]
Expenses for initial public offering					875,000
Maximum
Organization And Nature Of Business [Line Items]
Shelf registration statement, aggregate dollar amount						150,000,000
COMMON STOCK
Organization And Nature Of Business [Line Items]
Common stock initial public offering			7,728,000
Cantor Fitzgerald and Co. | COMMON STOCK | Maximum
Organization And Nature Of Business [Line Items]
Shelf registration statement, aggregate dollar amount						$50,000,000

Significant_Accounting_Policie3

Significant Accounting Policies - Schedule of Computation of Diluted EPS (Details)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Convertible notes payable
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common stock equivalents excluded from the computation of diluted net loss per share	5,040,323		0		0
Convertible preferred stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common stock equivalents excluded from the computation of diluted net loss per share	0	[1]	0	[1]	12,120,531	[1]
Outstanding stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common stock equivalents excluded from the computation of diluted net loss per share	3,826,459		3,189,660		1,554,200
Notes payable, related party
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common stock equivalents excluded from the computation of diluted net loss per share	0	[1]	0	[1]	3,016,000	[1]
Stock purchase warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common stock equivalents excluded from the computation of diluted net loss per share	309,506		309,506		595,869
Unvested restricted common stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential common stock equivalents excluded from the computation of diluted net loss per share	103,064		246,068		0
[1]	In connection with the completion of the Company’s IPO, the outstanding shares of convertible preferred stock and outstanding notes to related parties and accrued interest thereon were converted into 12,120,531 and 1,860,363 shares of common stock, respectively.

Significant_Accounting_Policie4

Significant Accounting Policies - Additional Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	Financial_Institution
	Segment
Accounting Policies [Abstract]
Long-term debt, fair value		$0
Debt Conversion [Line Items]
Number of operating segments	1
Reverse stock split, conversion ratio	0.2
Cash equivalents maturity period	3 months
Number of financial institutions	6
Amount insured by FDIC	250,000
Tax benefits recognized for stock-based compensation	0
Warrants exercise price	$0.05
Debt conversion, shares issued	1,860,363
CONVERTIBLE PREFERRED STOCK
Debt Conversion [Line Items]
Debt conversion, shares issued	12,120,531
Convertible notes payable
Debt Conversion [Line Items]
Debt conversion, shares issued	1,860,363
Convertible debt | 2014 Notes
Debt Conversion [Line Items]
Ownership cap for holder and affiliates, percentage	9.99%
Domestic tax authority
Debt Conversion [Line Items]
Operating loss carry-forwards	133,600,000
Convertible debt | 2014 Notes
Accounting Policies [Abstract]
Long-term debt, fair value	$163,800,000
Debt Conversion [Line Items]
Ownership cap for holder and affiliates, percentage	9.99%

Significant_Accounting_Policie5

Significant Accounting Policies - Operating Loss Carryforwards (Details) (Domestic tax authority, USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Domestic tax authority
Operating Loss Carryforwards [Line Items]
Net operating loss carry-forwards	$133.60

Other_Income_Expense_Net_Detai

Other Income (Expense), Net (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Other Income and Expenses [Abstract]
Interest and amortization expense	($628)		($3,795)		($75)
Loss on conversion of notes payable to related parties	0		-2,737		0
Sale of New Jersey state tax benefit	2,288		1,268		0
Expense due to change in fair value measurements	0	[1]	-3,717	[1]	-630	[1]
Other income, net	179		3		20
Other income (expense), net	$1,839		($8,978)		($685)
[1]	Includes change in fair value of warrant liabilities and change in fair value of a certain conversion feature related to the 2012 Notes (as defined herein) that was determined to be an embedded derivative requiring bifurcation and separate accounting. See Note 12 and Note 8, respectively.

Investments_Details

Investments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Investment [Line Items]
Cash and cash equivalents	$85,586	$69,649	$2,925	$15,068
Investments, amortized cost	72,721
Investments, gross unrealized gains	2
Investments, gross unrealized losses	-109
Investments, fair value	72,614
Total cash, cash equivalents, and investments, amortized cost	158,307
Total cash, cash equivalents, and investments, fair value	158,200
Certificates of deposit, due within one year
Investment [Line Items]
Investments, amortized cost	25,823
Investments, gross unrealized gains	0
Investments, gross unrealized losses	-9
Investments, fair value	25,814
Certificates of deposit, due within two years
Investment [Line Items]
Investments, amortized cost	4,429
Investments, gross unrealized gains	1
Investments, gross unrealized losses	-3
Investments, fair value	4,427
Commercial paper
Investment [Line Items]
Investments, amortized cost	5,988
Investments, gross unrealized gains	1
Investments, gross unrealized losses	-3
Investments, fair value	5,986
Corporate bonds, due within 1 year
Investment [Line Items]
Investments, amortized cost	16,487
Investments, gross unrealized gains	0
Investments, gross unrealized losses	-24
Investments, fair value	16,463
Corporate bonds, due within 2 years
Investment [Line Items]
Investments, amortized cost	13,912
Investments, gross unrealized gains	0
Investments, gross unrealized losses	-64
Investments, fair value	13,848
US Government agencies short-term debt securities
Investment [Line Items]
Investments, amortized cost	6,082
Investments, gross unrealized gains	0
Investments, gross unrealized losses	-6
Investments, fair value	6,076
Cash and money market accounts
Investment [Line Items]
Cash and cash equivalents	84,613
Certificates of deposit
Investment [Line Items]
Cash and cash equivalents	472
Corporate bond securities
Investment [Line Items]
Cash and cash equivalents	$501

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	$85,586,000	$69,649,000
Investments, fair value	30,241,000
Commercial paper, fair value	5,986,000
Corporate bonds, fair value	30,311,000
Government agencies, fair value	6,076,000
Total investments, fair value	72,614,000
Cash, cash equivalents, and investments, fair value	158,200,000
Long-term debt, fair value		0
Fair value, inputs, level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	84,613,000	69,649,000
Investments, fair value	0
Commercial paper, fair value	0
Corporate bonds, fair value	0
Government agencies, fair value	0
Total investments, fair value	0
Cash, cash equivalents, and investments, fair value	84,613,000
Fair value, inputs, level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	973,000	0
Investments, fair value	30,241,000
Commercial paper, fair value	5,986,000
Corporate bonds, fair value	30,311,000
Government agencies, fair value	6,076,000
Total investments, fair value	72,614,000
Cash, cash equivalents, and investments, fair value	73,587,000
Fair value, inputs, level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	0	0
Investments, fair value	0
Commercial paper, fair value	0
Corporate bonds, fair value	0
Government agencies, fair value	0
Total investments, fair value	0
Cash, cash equivalents, and investments, fair value	0
Cash and money market accounts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	84,613,000	69,649,000
Cash and money market accounts | Fair value, inputs, level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	84,613,000	69,649,000
Cash and money market accounts | Fair value, inputs, level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	0	0
Cash and money market accounts | Fair value, inputs, level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	0	0
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	472,000
Certificates of deposit | Fair value, inputs, level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	0
Certificates of deposit | Fair value, inputs, level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	472,000
Certificates of deposit | Fair value, inputs, level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	0
Corporate bond securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	501,000
Corporate bond securities | Fair value, inputs, level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	0
Corporate bond securities | Fair value, inputs, level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	501,000
Corporate bond securities | Fair value, inputs, level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents, fair value	0
Convertible debt | 2014 Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value	$163,800,000

Furniture_Fixtures_and_Equipme2

Furniture, Fixtures and Equipment, Net - Furniture, Fixtures and Equipment, Net (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$1,263	$1,082
Less: Accumulated depreciation	-1,023	-950
Property and equipment, net	240	132
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Estimated Useful Lives	7 years
Property and equipment, gross	830	789
Software and computer equipment
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Estimated Useful Lives	3 years
Property and equipment, gross	195	142
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Estimated Useful Lives	5 years
Property and equipment, gross	$238	$151

Furniture_Fixtures_and_Equipme3

Furniture, Fixtures and Equipment, Net - Additional Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Abstract]
Depreciation expense	$73	$64	$138

Accounts_Payable_Other_Current2

Accounts Payable & Other Current Liabilities (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
Payables and Accruals [Abstract]
Accounts payable	$2,068		$1,442
Accrued expenses and other liabilities:
Employee benefits and compensation related accruals	2,257	[1]	966	[1]
General and administrative related accruals	731		411
Research and development related accruals	3,280		663
Accounts payable and other current liabilities	$8,336		$3,482
[1]	Comprised of accrued bonus, accrued vacation, accrued severance liabilities, and liabilities under the Company’s employee stock purchase plan.

Convertible_Notes_2012_Notes_D

Convertible Notes - 2012 Notes (Details) (USD $)	12 Months Ended	0 Months Ended
	Dec. 31, 2014	Oct. 30, 2013	Dec. 07, 2012	Dec. 31, 2013	Sep. 30, 2013	Aug. 09, 2013	23-May-13	Mar. 28, 2013
			Note
Short-term Debt [Line Items]
Principal and accrued interest outstanding shares converted into common stock	1,860,363
Conversion price of notes		$10
2012 Notes | Initial public offer
Short-term Debt [Line Items]
Principal and accrued interest outstanding shares converted into common stock		1,860,363
Conversion price of notes		$10
2012 Notes | Convertible debt
Short-term Debt [Line Items]
Convertible notes, interest rate			8.00%
Convertible notes authorized and available for sale			$15,000,000	$12,000,000
Convertible notes, aggregate principal balance			3,000,000			4,500,000	4,500,000	3,000,000
Number of individual convertible notes			5
Additional convertible notes authorized						3,000,000
Aggregate convertible notes authorized						18,000,000
Aggregate proceeds	3,000,000
Fair value of embedded derivative	0				$96,000

Convertible_Notes_Reconciliati

Convertible Notes - Reconciliation of Convertible Debt (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Disclosure [Abstract]
Convertible Debt	$125,000
Unamortized debt discounts	875
Debt Instrument, Amortization of Debt Discount	31
Debt Instrument, Increase (Decrease), Other, Net	$124,156	$0

Convertible_Notes_2014_Notes_D

Convertible Notes - 2014 Notes (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Oct. 30, 2013	Sep. 30, 2014
Debt Instrument [Line Items]
Unamortized debt discounts	$875,000
Conversion price of notes		$10
Convertible debt | 2014 Notes
Debt Instrument [Line Items]
Interest Expense, Debt	551,000
Convertible notes, interest rate			1.75%
Ownership cap for holder and affiliates, percentage	9.99%
Default provisions, qualifying percentage of ownership	50.00%
Unamortized debt discounts			875,000
Conversion price of notes	$24.80
Initial conversion rate	40.32
Initial conversion, premium over closing price	30.00%
Maximum increase to initial conversion rate	12.07
Debt instrument, convertible, stock price trigger	$30
Debt instrument, convertible, threshold trading days	30
Transaction fee for debt issuance	625,000
Debt instrument, fee amount	250,000
Legal fees	$1,300,000

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Tax Credit Carryforward [Line Items]
Increase in deferred income tax valuation allowance	$10.70	$11.10	$6.10
Reduction attributable to transfer of deferred state tax benefits to an unrelated third party	2.5
Net operating loss and research and development tax credits carry-forwards, offset period	expire from 2024 through 2032
Research tax credit carryforward
Tax Credit Carryforward [Line Items]
Federal research and development tax credit carryforward	0.6
U.S. federal state and local tax
Tax Credit Carryforward [Line Items]
Provision for U.S. federal or state income taxes	0
Domestic tax authority
Tax Credit Carryforward [Line Items]
Net operating loss carry-forwards	133.6
State and local jurisdiction
Tax Credit Carryforward [Line Items]
Net operating loss carry-forwards	136.6
Non-qualified stock options
Tax Credit Carryforward [Line Items]
Net operating loss carry-forwards	$8.30

Income_Taxes_Summary_of_Signif

Income Taxes - Summary of Significant Components of Company's Net Deferred Income Tax Assets (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Net deferred tax assets:
Tax loss carry-forwards	$42,863	$35,428
Other assets	4,882	1,742
Research and development credits	631	556
Other liabilities	-693	-782
Valuation allowance	-47,683	-36,944
Total net deferred income taxes	$0	$0

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of U.S. Statutory Rate and Effective Tax Rate (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
U.S. federal tax rate	35.00%	35.00%	35.00%
State tax rate	6.13%	5.36%	5.17%
Other	-0.04%	-0.03%	-0.02%
Valuation allowance	-41.09%	-40.33%	-40.15%
Effective tax rate	0.00%	0.00%	0.00%

Convertible_Preferred_Stock_De

Convertible Preferred Stock (Details) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended
	Oct. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 23, 2011	Dec. 07, 2012
Permanent And Temporary Equity [Line Items]
Conversion of preferred stock into common stock	12,120,531
Preferred stock, shares authorized		0				16,534,582
Accretion amount		$0	$210,000	$258,000
Accretion amount		0	240,000	292,000
Convertible preferred stock series B
Permanent And Temporary Equity [Line Items]
Issuance of Convertible Preferred Stock					23,800,000
Stock issuance costs					1,200,000
Series A-1 preferred stock
Permanent And Temporary Equity [Line Items]
Preferred stock, shares authorized			400,000
Series A-2 preferred stock
Permanent And Temporary Equity [Line Items]
Preferred stock, shares authorized			2,002,006
Series A-3 preferred stock
Permanent And Temporary Equity [Line Items]
Preferred stock, shares authorized			4,495,895
Series A-4 preferred stock
Permanent And Temporary Equity [Line Items]
Preferred stock, shares authorized			1,136,681
Series B preferred stock
Permanent And Temporary Equity [Line Items]
Preferred stock, shares authorized			8,500,000
CONVERTIBLE PREFERRED STOCK
Permanent And Temporary Equity [Line Items]
Accretion amount			210,000	258,000
Convertible preferred stock series A-4
Permanent And Temporary Equity [Line Items]
Difference between stated and fair value					1,300,000
Accretion amount			$240,000	$292,000

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended
In Thousands, except Share data, unless otherwise specified	Oct. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Nov. 10, 2014	Oct. 24, 2013
Class of Stock [Line Items]
Common stock, shares issued	7,728,000
Common stock, offering price per share	$10
Net proceeds from initial public offering	$68,300	$0	$71,870	$0
Underwriting discounts and commissions	5,410
Payments of initial public offering costs	3,644	0	3,644	0
Conversion of convertible securities to common stock	12,120,531
Debt conversion, shares issued		1,860,363
Debt conversion, conversion price per share	$10
Common stock, shares authorized	150,000,000	150,000,000	150,000,000
Common stock, par value	$0.00	$0.00	$0.00
Decrease in preferred stock	15,000,000	15,000,000	15,000,000
Preferred stock, par value	$0.00	$0.00	$0.00
Convertible Preferred Stock
Class of Stock [Line Items]
Warrants to purchase common stock		1,275,680
COMMON STOCK
Class of Stock [Line Items]
Common stock, shares issued			7,728,000
Conversion of convertible securities to common stock			12,120,531
Stock offering underwriter overallotment option
Class of Stock [Line Items]
Common stock, shares issued	1,008,000
Employee stock purchase plan
Class of Stock [Line Items]
Equity awards	645,814
2013 equity plan
Class of Stock [Line Items]
Equity awards	3,229,068
Maximum
Class of Stock [Line Items]
Shelf registration statement, aggregate dollar amount					150,000
Conversion one | Convertible Preferred Stock
Class of Stock [Line Items]
Warrants exercise to purchase convertible preferred stock						297,366
Conversion of convertible securities to common stock	297,366
Conversion two | Convertible Preferred Stock
Class of Stock [Line Items]
Warrants exercise to purchase convertible preferred stock	186,248
Conversion of convertible securities to common stock	186,248
Conversion three | Convertible Preferred Stock
Class of Stock [Line Items]
Conversion of convertible securities to common stock	12,120,531
Conversion four
Class of Stock [Line Items]
Warrants to purchase common stock	717,801
Conversion four | Convertible Preferred Stock
Class of Stock [Line Items]
Warrants to purchase common stock	717,801
Cantor Fitzgerald and Co. | Maximum | COMMON STOCK
Class of Stock [Line Items]
Shelf registration statement, aggregate dollar amount					$50,000

Stock_Purchase_Warrants_Schedu

Stock Purchase Warrants - Schedule of Warrants Outstanding (Details) (USD $)	12 Months Ended
	Dec. 31, 2014
Class of Warrant or Right [Line Items]
EXERCISE PRICE PER SHARE	$0.05
March 2016 | COMMON STOCK
Class of Warrant or Right [Line Items]
Class Of Warrant Or Right Expiration Year And Month	2016-03
NUMBER OF UNDERLYING SHARES	2,006
EXERCISE PRICE PER SHARE	$5
February 2019 | COMMON STOCK
Class of Warrant or Right [Line Items]
Class Of Warrant Or Right Expiration Year And Month	2019-02
NUMBER OF UNDERLYING SHARES	75,000
EXERCISE PRICE PER SHARE	$5
November 2019 | COMMON STOCK
Class of Warrant or Right [Line Items]
Class Of Warrant Or Right Expiration Year And Month	2019-11
NUMBER OF UNDERLYING SHARES	75,000
EXERCISE PRICE PER SHARE	$5
August 2020 | COMMON STOCK
Class of Warrant or Right [Line Items]
Class Of Warrant Or Right Expiration Year And Month	2020-08
NUMBER OF UNDERLYING SHARES	157,500
EXERCISE PRICE PER SHARE	$5
December 2019 | COMMON STOCK
Class of Warrant or Right [Line Items]
Class Of Warrant Or Right Expiration Year And Month	2019-12
NUMBER OF UNDERLYING SHARES	408,295
EXERCISE PRICE PER SHARE	$0.05

Stock_Purchase_Warrants_Schedu1

Stock Purchase Warrants - Schedule of Key Assumptions Utilized in Fair Value Calculation (Details) (Convertible Preferred Stock Warrants [Member])	0 Months Ended	12 Months Ended
	Oct. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Volatility	65.00%	60.00%	108.74%
Dividend yield	0.00%	0.00%	0.00%
Minimum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected term (years)	5 years 3 months 26 days	6 years 1 month 17 days	7 years 1 month 17 days
Risk-free interest rate	1.51%	0.98%	1.37%
Maximum
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected term (years)	6 years 10 months 2 days	7 years 7 months 28 days	8 years 7 months 24 days
Risk-free interest rate	2.00%	1.31%	1.64%

Stock_Purchase_Warrants_Additi

Stock Purchase Warrants - Additional Information (Details)	0 Months Ended	12 Months Ended
	Oct. 30, 2013	Dec. 31, 2014	Dec. 31, 2006	Oct. 24, 2013
Class of Warrant or Right [Line Items]
Conversion of convertible securities to common stock	12,120,531
Weighted average remaining lives		4 years 11 months 27 days
Conversion four
Class of Warrant or Right [Line Items]
Number of shares of convertible preferred stock into which the warrants may be converted	717,801
Two thousand six warrants
Class of Warrant or Right [Line Items]
Term of warrant		10 years
Two thousand ten warrants
Class of Warrant or Right [Line Items]
Term of warrant		10 years
Two thousand twelve warrants
Class of Warrant or Right [Line Items]
Term of warrant		7 years
Convertible preferred stock series A-2
Class of Warrant or Right [Line Items]
Number of shares of convertible preferred stock into which the warrants may be converted			2,006
Convertible Preferred Stock
Class of Warrant or Right [Line Items]
Number of shares of convertible preferred stock into which the warrants may be converted		1,275,680
Convertible Preferred Stock | Conversion four
Class of Warrant or Right [Line Items]
Number of shares of convertible preferred stock into which the warrants may be converted	717,801
Convertible Preferred Stock | Conversion two
Class of Warrant or Right [Line Items]
Warrants exercise to purchase convertible preferred stock	186,248
Conversion of convertible securities to common stock	186,248
Convertible Preferred Stock | Conversion one
Class of Warrant or Right [Line Items]
Warrants exercise to purchase convertible preferred stock				297,366
Conversion of convertible securities to common stock	297,366

Stockbased_Compensation_Stockb

Stock-based Compensation - Stock-based Compensation Expense for Options Granted and Restricted Stock as Reflected in the Statement of Operations (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$9,178	$2,858	$430
Research and development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,339	222	89
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$7,839	$2,636	$341

Stockbased_Compensation_Schedu

Stock-based Compensation - Schedule of Stock Options Activity (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, beginning, number of shares	3,189,660	1,554,200	1,152,194
Granted, number of shares	1,263,100	2,009,551	575,200
Exercised, number of shares	-592,044	-3,195	-12,907
Cancelled, number of shares	-34,257	-370,896	-160,287
Options outstanding, ending, number of shares	3,826,459	3,189,660	1,554,200
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price, beginning (in usd per share)	$2.16	$1.39	$0.31
Granted, weighted average exercise price (in usd per share)	$20.38	$3.11	$1.45
Exercised, weighted average exercise price (in usd per share)	$0.42	$0.37	$0.39
Cancelled, weighted average exercise price (in usd per share)	$14.32	$1.38	$0.23
Options outstanding, weighted average exercise price, ending (in usd per share)	$8.39	$2.16	$1.39
Options exercisable at December 31, 2014, number of shares	1,329,347
Options exercisable at December 31, 2014, weighted average exercise price (in usd per share)	$2.18

Stockbased_Compensation_Schedu1

Stock-based Compensation - Schedule of Stock Options Outstanding and Exercisable Option Plans (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding	3,826,459
Options outstanding, weighted average exercise price	8.34
Options outstanding, aggregate intrinsic value	79,792
Options exercisable	1,329,347
Options exercisable, weighted average exercisable price	2.18
Options exercisable, aggregate intrinsic value	35,911
Exercise price one
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding	2,591,459
Options outstanding, weighted average remaining contractual life	8 years
Options exercisable	1,327,012
Exercise price two
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding	180,500
Options outstanding, weighted average remaining contractual life	9 years 3 months 18 days
Options exercisable	0
Exercise price three
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding	969,700
Options outstanding, weighted average remaining contractual life	9 years 2 months 12 days
Options exercisable	2,335
Exercise price four
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding	84,800
Options outstanding, weighted average remaining contractual life	9 years 8 months 12 days
Options exercisable	0
Minimum | Exercise price one
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower range limit	0.005
Minimum | Exercise price two
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower range limit	15.55
Minimum | Exercise price three
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower range limit	19.07
Minimum | Exercise price four
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower range limit	24.59
Maximum | Exercise price one
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, upper range limit	3.15
Maximum | Exercise price two
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, upper range limit	17.97
Maximum | Exercise price three
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, upper range limit	22.31
Maximum | Exercise price four
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, upper range limit	25.99

Stockbased_Compensation_Schedu2

Stock-based Compensation - Schedule of Key Assumptions Utilized in Fair Value Calculation (Details) (Stock options)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (years)	6 years 3 months	6 years 3 months	6 years 3 months
Expected stock price volatility	80.44%	79.20%	60.00%
Risk-free interest rate	1.90%	1.78%	1.05%
Dividend yield	0.00%	0.00%	0.00%

Stockbased_Compensation_Additi

Stock-based Compensation - Additional Information (Details) (USD $)	0 Months Ended	12 Months Ended
	Mar. 21, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, shares granted		1,263,100	2,009,551	575,200
Aggregate intrinsic value of options exercised		$10,500,000	$9,000	$10,000
Estimated fair value of common stock		$29.19	$17.96
Stock options cancelled	345,000
Restricted stock, shares issued	371,034
Stock-based compensation expense		9,178,000	2,858,000	430,000
2005 Aerie pharmaceutical stock plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, shares granted		0
Unrecognized compensation expense		23,100,000
Compensation cost, weighted average recognition period		2 years 7 months 6 days
Options outstanding, weighted average remaining contractual life		8 years 4 months 24 days
2013 equity plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity awards		3,229,068
Number of equity awards granted under plan to date		1,263,100
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity awards		634,873
Stock-based compensation expense		63,000	66,000
Minimum | 2005 Aerie pharmaceutical stock plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period		1 year
Maximum | 2005 Aerie pharmaceutical stock plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity awards		3,586,277
Stock-based awards, vesting period		5 years
Stock-based awards, expiration period		10 years
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost, weighted average recognition period		1 year 4 months 24 days
Restricted stock, unvested shares		103,064
Stock-based compensation expense		390,000	346,000
Unrecognized compensation expense		$242,000
Restricted stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period		2 years
Restricted stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based awards, vesting period		4 years

Commitments_and_Contingencies_1

Commitments and Contingencies - Summary of Future Minimum Lease Payments (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]
2014	$460
2015	309
2016	332
2017	328
2018	396
2019 and thereafter	267
Total minimum lease payments	$2,092

Commitments_and_Contingencies_2

Commitments and Contingencies - Additional Information (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$579	$403	$333

RelatedParty_Transactions_Deta

Related-Party Transactions (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 30, 2012	Sep. 06, 2012
Related Party Transaction [Line Items]
Interest expense		$588,000	$16,000
Cash dividend			130,000
Payment made to board members	333,000	190,000	34,000
Novaer
Related Party Transaction [Line Items]
Percentage of dividend distribution					100.00%
Cash dividend				100,000
Intellectual property | Novaer
Related Party Transaction [Line Items]
Cash for initial funding				100,000
Book value of non-core intellectual property					0

Benefit_Plan_Details

Benefit Plan (Details) (USD $)	0 Months Ended	12 Months Ended
	Oct. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum value of shares that can be purchased	$25,000
401 (K) Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee contribution, statutory limitation		17,500	17,500
Contributions by employer		$0	$0	$0
Employee stock purchase plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Purchase price of stock as a percentage of fair market value	85.00%
Shares reserved for future issuance		634,873

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	12 Months Ended			1 Months Ended	0 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 31, 2015	Feb. 25, 2015
Subsequent Event [Line Items]
Common stock option grants	1,263,100	2,009,551	575,200
Option exercise price	$20.38	$3.11	$1.45
Subsequent events
Subsequent Event [Line Items]
Transfer to state tax benefit				$3.10
Net proceeds from transfer of tax benefit				2.9
Operating leases, rent expense, minimum rentals				2.9
Subsequent events | Officer
Subsequent Event [Line Items]
Common stock option grants					363,750
Option exercise price					$28.03
Option term					4 years
Option vesting period					4 years
Aggregate fair value of option grants					$6.70
Irvine lease agreement for office space | Commercial office space | Subsequent events
Subsequent Event [Line Items]
Area of Real Estate Property				14,500

Selected_Quarterly_Financial_D2

Selected Quarterly Financial Data (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Operating expenses	($15,973)	($13,174)	($11,843)	($8,982)	($6,750)	($5,686)	($5,113)	($4,621)	($49,972)	($22,170)	($14,293)
Net loss attributable to common stockholders	($16,501)	($13,147)	($11,814)	($6,671)	($10,319)	($10,887)	($6,465)	($3,927)	($48,133)	($31,598)	($15,643)
Net loss per share attributable to common stockholders—basic and diluted	($0.69)	($0.54)	($0.49)	($0.28)	($0.62)	($10.81)	($6.59)	($4.07)	($2)	($6.38)	($16.39)