Hyperion Therapeutics (HPTX) Inactive 10-K4 Mar 152014 FY Annual reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	Dec. 31, 2014	Feb. 27, 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	HPTX
Entity Registrant Name	HYPERION THERAPEUTICS INC
Entity Central Index Key	1386858
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		20,774,744
Entity Public Float			$420,544,733

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets
Cash and cash equivalents	$102,796	$74,232
Short-term investments	34,487	28,045
Accounts receivable, net	14,864	4,419
Inventories, net	4,621	3,513
Prepaid expenses and other current assets	2,632	1,403
Total current assets	159,400	111,612
Long-term investments	9,226	15,780
Property and equipment, net	1,116	936
Intangible asset, net	8,816	13,442
Other non-current assets	1,858	749
Total assets	180,416	142,519
Current liabilities
Accounts payable	4,669	2,292
Accrued liabilities	25,509	12,187
Deferred revenue	224
Notes payable, current portion		5,652
Total current liabilities	30,402	20,131
Notes payable, net of current portion	18,124	2,621
Deferred rent	338	81
Total liabilities	48,864	22,833
Commitments and contingencies (Note 13)
Stockholders' equity
Preferred stock, par value $0.0001 - 10,000,000 shares authorized at December 31, 2014 and 2013; none issued and outstanding
Common stock, par value $0.0001 - 100,000,000 shares authorized at December 31, 2014 and 2013; 20,747,013 and 20,137,145 shares issued and outstanding at December 31, 2014 and 2013, respectively	2	2
Additional paid-in capital	260,225	242,109
Accumulated other comprehensive loss	-50	-55
Accumulated deficit	-128,625	-122,370
Total stockholders' equity	131,552	119,686
Total liabilities and stockholders' equity	$180,416	$142,519

Condensed_Consolidated_Balance1

Condensed Consolidated 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	10,000,000	10,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	20,747,013	20,137,145
Common stock, shares outstanding	20,747,013	20,137,145

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net product revenue	$113,584	$42,204
Costs and expenses:
Cost of sales	13,727	6,740
Research and development	20,715	9,984	17,046
Selling, general and administrative	48,522	35,839	11,487
Impairment of goodwill (Notes 4 and 8)	30,201
Amortization of intangible asset	4,626	3,058
Total costs and expenses	117,791	55,621	28,533
Loss from operations	-4,207	-13,417	-28,533
Interest income	555	27	12
Interest expense	-1,601	-1,539	-3,703
Gain from settlement of retention option (Note 4)		31,079
Other income (expense), net	-699	526	-39
Income (loss) before income taxes	-5,952	16,676	-32,263
Income tax expense	303	49
Net income (loss)	($6,255)	$16,627	($32,263)
Net income (loss) per share:
Basic	($0.31)	$0.86	($4.45)
Diluted	($0.31)	$0.80	($4.45)
Weighted average number of shares used to compute net income (loss) per share of common stock:
Basic	20,470,025	19,415,822	7,256,537
Diluted	20,470,025	20,730,913	7,256,537

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Loss) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income (loss)	($6,255)	$16,627	($32,263)
Other comprehensive income (loss):
Unrealized gain (loss) on investments arising during the year	5	-55
Other comprehensive income (loss)	5	-55
Comprehensive income (loss)	($6,250)	$16,572	($32,263)

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (Deficit) (USD $)	Total	Initial Public Offering	Follow-on offering	Convertible Notes Payable	Convertible preferred stock	Common Stock [Member]	Common Stock [Member]	Common Stock [Member]	Common Stock [Member]	Additional Paid-in Capital	Additional Paid-in Capital	Additional Paid-in Capital	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Deficit
In Thousands, except Share data	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	USD ($)	Initial Public Offering	Follow-on offering	Convertible Notes Payable	USD ($)	Initial Public Offering	Follow-on offering	Convertible Notes Payable	USD ($)	USD ($)
							USD ($)				USD ($)	USD ($)	USD ($)
Balance at Dec. 31, 2011	($82,104)				$58,326					$24,630					($106,734)
Balance, shares at Dec. 31, 2011					6,575,637	469,319
Issuance of stock		51,312					1				51,311
Issuance of stock (in shares)							5,750,000
Issuance of common stock upon conversion of convertible securities	58,326				-58,326	1				58,325
Issuance of common stock upon conversion of convertible securities (in shares)					-6,575,637	6,575,637
Conversion of convertible notes payable and accrued interest to common stock	33,322			33,322									33,322
Conversion of convertible notes payable and accrued interest to common stock, (in shares)									3,444,870
Issuance of common stock upon automatic net exercise of warrants	3,901									3,901
Issuance of common stock upon automatic net exercise of warrants (in shares)						340,361
Issuance of common stock warrant	755									755
Issuance of common stock upon exercise of stock options	147									147
Issuance of common stock upon exercise of stock options (in shares)						66,082
Stock-based compensation expense	993									993
Net income (loss)	-32,263														-32,263
Balance at Dec. 31, 2012	34,389					2				173,384					-138,997
Balance, shares at Dec. 31, 2012						16,646,269
Issuance of stock			63,712									63,712
Issuance of stock (in shares)								3,306,250
Exercise of common stock warrants (in shares)									67,503
Issuance of common stock upon exercise of stock options	637									637
Issuance of common stock upon exercise of stock options (in shares)						117,123
Stock-based compensation expense	4,376									4,376
Other comprehensive income(loss)	-55													-55
Net income (loss)	16,627														16,627
Balance at Dec. 31, 2013	119,686					2				242,109				-55	-122,370
Balance, shares at Dec. 31, 2013						20,137,145
Issuance of common stock upon exercise of stock options	2,583									2,583
Issuance of common stock upon exercise of stock options (in shares)						291,999
Issuance of common stock upon release of restricted stock units	0				0	0				0				0	0
Issuance of common stock upon release of restricted stock units (in shares)						5,000
Issuance of common stock upon acquisition of Andromeda Biotech Ltd (Note 4)	7,778									7,778
Issuance of common stock upon acquisition of Andromeda Biotech Ltd (Note 4) (in shares)						312,869
Stock-based compensation expense	7,647									7,647
Excess tax benefit from stock-based compensation	108									108
Other comprehensive income(loss)	5													5
Net income (loss)	-6,255														-6,255
Balance at Dec. 31, 2014	$131,552					$2				$260,225				($50)	($128,625)
Balance, shares at Dec. 31, 2014						20,747,013

Consolidated_Statements_of_Sto1

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Statement of Stockholders' Equity [Abstract]
Underwriting discounts and commissions	$4,116	$4,025
Offering costs	$776	$2,163

Condensed_Consolidated_Stateme2

Condensed Consolidated 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 income (loss)	($6,255)	$16,627	($32,263)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities
Depreciation	496	198	15
Amortization of debt discount and debt issuance costs	627	556	1,381
Re-measurement of warrants liability			780
Re-measurement of call option liability and preferred stock liability			-737
Stock-based compensation expense	7,568	4,294	993
Amortization of intangible asset	4,626	3,058
Impairment of goodwill (Notes 4 and 8)	30,201
Gain from settlement of retention option (Note 4)		-31,079
Unrealized loss on foreign currency translation adjustments	7	14
Provision of inventory obsolescence	346
Amortization of discount on available-for-sale investments	397	51
Excess tax benefit from stock-based compensation	-108
Changes in assets and liabilities, net of impact of acquisition of Andromeda Biotech Ltd. ("Andromeda")
Accounts receivable	-10,452	-4,433
Inventories	-1,376	468
Prepaid expenses and other assets	-1,705	-809	-249
Accounts payable	-1,857	115	290
Accrued liabilities and other	7,978	9,647	1,259
Deferred revenue	224
Deferred rent	281	81
Net cash provided by (used in) operating activities	30,998	-1,212	-28,531
Cash flows from investing activities
Acquisition of property and equipment	-654	-1,085	-45
Purchase of available-for-sale investments	-29,023	-43,931
Maturity of available-for-sale investments	28,743
Acquisition of Andromeda, net of cash acquired	-14,039
Option to purchase BUPHENYL and AMMONUL (Note 4)			-283
Acquisition of rights to BUPHENYL, net of AMMONUL option (Note 4)		10,962
Change in restricted cash			330
Net cash provided by (used in) investing activities	-14,973	-34,054	2
Cash flows from financing activities
Proceeds from issuance of common stock in initial public offering, net of underwriting discounts			53,475
Proceeds from issuance of common stock in follow-on offering, net of underwriting discounts		64,488
Proceeds from issuance of common stock from stock option exercises	2,584	637	147
Proceeds from term loans	16,000
Proceeds from revolving credit line	2,000
Excess tax benefit from stock-based compensation	108
Proceeds from issuance of convertible notes payable			7,504
Proceeds from issuance of notes payable, net of issuance costs			12,401
Payments of offering costs		-1,132	-2,163
Principal payments under notes payable	-8,153	-4,348
Net cash provided by financing activities	12,539	59,645	71,364
Net increase in cash and cash equivalents	28,564	24,379	42,835
Cash and cash equivalents, beginning of period	74,232	49,853	7,018
Cash and cash equivalents, end of period	102,796	74,232	49,853
Supplemental cash flow information
Cash paid for interest	1,526	966	593
Cash paid for income tax	1,099
Stock-based compensation capitalized into inventories	79	82
Supplemental disclosure of noncash investing and financing activities
Warrants issued in connection with notes payable			1,302
Option to purchase rights to BUPHENYL and AMMONUL (Note 4)		283
Unrealized gain (loss) on available-for-sale investments	5	-55
Issuance of common stock upon automatic net exercise of warrants			3,901
Conversion of convertible notes payable and accrued interest to common stock			33,322
Conversion of Series C-1 and C-2 preferred stock to common stock			58,326
Acquisition of Andromeda (Note 4)
Cash paid for acquisition	14,345
Cash acquired in acquisition	-306
Net cash paid for acquisition	14,039
Fair value of common stock issued in connection with the acquisition	$7,778

Formation_and_Business_of_the_

Formation and Business of the Company	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Formation and Business of the Company	1	Formation and Business of the Company
	Hyperion Therapeutics, Inc. (the “Company”) was incorporated in the state of Delaware on November 1, 2006. The Company was in the development stage from inception through March 31, 2013. During this period, the Company’s activities consisted primarily of raising capital, negotiating a promotion and drug development collaboration agreement, establishing a management team and performing drug development activities. The Company launched RAVICTI^® (glycerol phenylbutyrate) Oral Liquid during the quarter ended March 31, 2013.
	On May 31, 2013, the Company acquired BUPHENYL, an FDA-approved therapy for treatment of three of the most prevalent UCD subtypes, from Ucyclyd Pharma Inc. (“Ucyclyd”), a subsidiary of Valeant Pharmaceuticals International, Inc. (“Valeant”). Subsequent to the acquisition on May 31, 2013, the Company started selling BUPHENYL Tablets and Powder within and outside the United States. The Company pays Ucyclyd royalties on net sales in the United States of BUPHENYL to UCD patients outside of the FDA-approved labeled age range for RAVICTI.
	As discussed in Note 4, on June 12, 2014, the Company completed the acquisition of Andromeda Biotech Ltd. (“Andromeda”), an Israeli company. On September 8, 2014 the Company announced that it was terminating development of DiaPep277^® for newly diagnosed Type 1 diabetes as a result of evidence that the Company uncovered that certain employees of Andromeda engaged in serious misconduct that compromised clinical trial results. The Company subsequently terminated the Andromeda employees involved in the misconduct. On September 22, 2014, Clal Biotechnology Industries Ltd., (“CBI”), the former owner of Andromeda filed suit against the Company in Delaware related to the Company’s announcement. On October 6, 2014 the Company entered into an interim agreement with CBI, to attempt to resolve their disputes. As discussed in Note 22, on January 16, 2015, CBI dismissed its claim against the Company without prejudice and the Company, CBI and Yeda Research and Development Company Ltd (“Yeda”) announced that they had reached an agreement to settle their disputes on February 16, 2015.
	The Company is a commercial biopharmaceutical company focused on the development and commercialization of novel therapeutics to treat disorders in the areas of orphan diseases. The Company’s products RAVICTI^® (glycerol phenylbutyrate) Oral liquid, BUPHENYL^® and AMMONAPS^® (sodium phenylbutyrate) Tablets and Powder, are designed to lower ammonia in the blood. Ammonia is produced in the intestine after a person eats protein and is normally detoxified in the liver by conversion to urea. Elevated levels of ammonia are potentially toxic and can lead to severe medical complications which may include death. The Company developed RAVICTI, which was launched during the first quarter of 2013, to treat most urea cycle disorders (“UCD”) and is developing glycerol phenylbutyrate (“GPB”), the active pharmaceutical ingredient in RAVICTI, to treat hepatic encephalopathy (“HE”). UCD and HE are diseases in which blood ammonia is elevated. UCD are inherited rare genetic diseases caused by a deficiency of one or more enzymes or transporters that constitute the urea cycle, which in a healthy individual removes ammonia through its conversion to urea. HE may develop in some patients with liver scarring, known as cirrhosis, or acute liver failure and is a chronic complication of cirrhosis which fluctuates in severity and may lead to serious neurological damage.
	On February 1, 2013, the U.S. Food and Drug Administration (“FDA”), granted approval of RAVICTI for the use as a nitrogen-binding agent for chronic management of adult and pediatric UCD patients greater than two years of age who cannot be managed by dietary protein restriction and/or amino acid supplementation alone.
	On July 31, 2012, the Company completed its initial public offering (“IPO”) and issued 5,000,000 shares of its common stock at an initial offering price of $10.00 per share. In addition, the Company sold an additional 750,000 shares of common stock directly to its underwriters when they exercised their over-allotment option in full at the initial offering price of $10.00 per share. The shares began trading on the NASDAQ Global Market on July 26, 2012. The Company received net proceeds from the IPO of $51.3 million, after deducting underwriting discounts and commissions of $4.0 million and expenses of $2.2 million. Upon the closing of the IPO, the Company’s Series C-1 and Series C-2 preferred stock converted into 1,912,598 and 4,663,039 shares of common stock, respectively. In addition, the principal and accrued interest under the Company’s April 2011 Notes and October 2011 Notes amounting to $18.9 million and $15.6 million, respectively, converted into 1,888,054 and 1,556,816 shares of common stock. As of July 31, 2012, the carrying value of the April 2011 Notes including the impact of the amendment to the April 2011 Notes and accrued interest was $18.4 million. As of July 31, 2012, the carrying value (net of discount) and accrued interest under the October 2011 Notes was $14.9 million. Additionally, the April 2011 common stock warrants and October 2011 preferred stock warrants were converted into 322,599 and 17,762 shares of common stock, respectively, immediately prior to the closing of the IPO.
	On March 13, 2013, the Company completed its follow-on offering and issued 2,875,000 shares of its common stock at an offering price of $20.75 per share. In addition, the Company sold an additional 431,250 shares of common stock directly to its underwriters when they exercised their over-allotment option in full at the offering price of $20.75 per share. The Company received net proceeds from the offering of $63.7 million, after deducting underwriting discounts and commissions of $4.1 million and expenses of $0.8 million.
	On August 14, 2013, the Company filed a shelf registration statement on Form S-3, which was declared effective by the Securities and Exchange Commission (“SEC”) on September 13, 2013. The shelf registration statement permits: (a) the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $150.0 million of its common stock, preferred stock, debt securities, warrants and/or units; (b) the sale of up to 8,727,000 shares of common stock by certain selling stockholders; and (c) the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $50.0 million of its common stock that may be issued and sold under a sales agreement with Cantor Fitzgerald & Co. As of December 31, 2014, there were no sales of any securities registered pursuant to the shelf registration statement.
	Since inception, the Company has incurred recurring annual net operating losses from operations. During the year ended December 31, 2014, the Company incurred a loss from operations of $4.2 million. At December 31, 2014, the Company had an accumulated deficit of $128.6 million. The Company expects to incur increased research and development expenses when it initiates a Phase 3 trial of GPB for the treatment of patients with episodic HE and completes the ongoing DIA AID 2 clinical trial of DiaPep277program. In addition, the Company expects to incur increased sales and marketing expenses with the continued commercialization of RAVICTI and marketing of BUPHENYL in UCD as it expands outside of the U.S. Management’s plans with respect to these matters include utilizing a substantial portion of the Company’s capital resources and efforts in completing the development and obtaining regulatory approval for GPB in HE, expanding the Company’s organization, commercialization of RAVICTI and marketing of BUPHENYL.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2	Summary of Significant Accounting Policies
	Basis of Presentation and the Use of Estimates
	The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The preparation of the accompanying consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to the fair value of assets and liabilities, intangible asset valuation, acquisition-related contingent consideration, acquisition related contingent liability, impairment of goodwill and intangible assets, stock-based compensation expense, income taxes, revenue recognition and product sales allowances. Management bases its estimates on historical experience or on various other assumptions, including information received from its service providers, which it believes to be reasonable under the circumstances. Actual results could differ from those estimates.
	Basis of Consolidation
	The consolidated financial statements include the Company’s accounts and those of its wholly-owned subsidiaries: Hyperion Therapeutics Ltd., Hyperion Therapeutics Ireland Holding Ltd., Hyperion Therapeutics Ireland Operating Ltd., Hyperion Therapeutics Israel Holding Corp. Ltd., Penville Limited and Andromeda Biotech Ltd. All intercompany accounts and transactions have been eliminated.
	Concentration of Credit Risk and Significant Customers
	The Company’s cash and cash equivalents and investments are maintained with financial institutions located in and outside the United States. Deposits in these institutions may exceed the amount of insurance provided on such deposits. The Company has not recognized any losses from credit risks during the periods presented and management does not believe that the Company is exposed to significant credit risk from its cash and cash equivalents or investments.
	The Company is also subject to credit risk from its accounts receivables related to its product sales. The Company monitors its exposure within accounts receivable and records a reserve against uncollectible accounts receivable as necessary. The Company extends credit to a specialty distributor in the United States and to international distributors, pharmacies and hospitals outside the United States. Customer creditworthiness is monitored and collateral is not required. As of December 31, 2014, there were no credit losses on the Company’s accounts receivable. As of December 31, 2014 and 2013, the specialty distributor in the United States accounted for 87% and 64% of accounts receivable balance, respectively. One international distributor accounted for 10% and 17% of the accounts receivable balance for the year ended December 31, 2014 and 2013, respectively.
	The specialty distributor accounted for 91% and 88% of the net product revenue for the year ended December 31, 2014 and 2013, respectively.
	Fair Value of Financial Instruments
	The Company measures certain financial assets and liabilities at fair value based on the exchange price that would be received for an asset or paid for 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 carrying amounts of the Company’s financial instruments, including cash equivalents, short-term investments, accounts payable, and accrued liabilities, approximate fair value due to their short maturities. The carrying amounts of long-term investments, acquisition-related contingent consideration and acquisition related contingent liability represent their estimated fair values. The fair value of the notes payable are based on the present value of expected future cash flows and assumptions about current interest rates and the creditworthiness of the Company.
	Business Combinations
	The Company allocates the purchase price of an acquired business to the tangible and intangible assets acquired and liabilities assumed based upon their estimated fair values on the acquisition date. Any excess of the purchase price over the fair value of the net assets acquired is recorded as goodwill. Acquired in-process research and development (“IPR&D”) is recognized at fair value and initially characterized as an indefinite-lived intangible asset, irrespective of whether the acquired IPR&D has an alternative future use. The purchase price allocation process requires management to make significant estimates and assumptions, especially at the acquisition date with respect to intangible assets. Direct transaction costs associated with the business combination are expensed as incurred.
	Cash and Cash Equivalents
	The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents include money market funds and various deposit accounts.
	Investments
	The Company determines the appropriate classification of its investments in debt and equity securities at the time of purchase. All of the Company’s securities are classified as available-for-sale and reported in short-term investments or long-term investments based on maturity dates and whether such assets are reasonably expected to be realized in cash or sold or consumed during the normal cycle of business. Available-for-sale investments are recorded at fair value, with unrealized gains or losses included in Accumulated Other Comprehensive Loss on the Company’s Consolidated Balance Sheets, exclusive of other-than-temporary impairment losses, if any. Short-term and long-term investments are comprised of corporate notes, commercial paper, U.S. federal government agency securities and certificates of deposit.
	Accounts Receivable
	Trade accounts receivable are recorded net of product sales allowances for prompt-payment discounts, chargebacks, and doubtful accounts. Estimates for chargebacks and prompt-payment discounts are based on contractual terms, historical trends and expectations regarding the utilization rates for these programs. At December 31, 2014, the Company had no allowances for doubtful accounts.
	Inventories
	Inventories are valued at the lower of cost or market, with cost computed at standard cost (which approximates actual cost) on a first-in-first-out (FIFO) cost method and consists of raw materials, work-in-progress and finished goods. Costs capitalized as inventories include third party manufacturing costs, associated compensation related costs of personnel indirectly involved in the manufacturing process and other overhead costs such as ancillary supplies. Subsequent to FDA approval of RAVICTI on February 1, 2013, the Company began capitalizing RAVICTI inventories as the related costs were expected to be recoverable through the commercialization of the product. Costs incurred prior to the FDA approval of RAVICTI have been recorded as research and development expense in the consolidated statements of operations. If information becomes available that suggest that inventories may not be realizable, the Company may be required to expense a portion or all of the previously capitalized inventories.
	Products that have been approved by the FDA or other regulatory authorities, such as RAVICTI, are also used in clinical programs, to assess the safety and efficacy of the products for usage in diseases that have not been approved by the FDA or other regulatory authorities. The form of RAVICTI utilized for both commercial and clinical programs is identical and, as a result, the inventory has an “alternative future use” as defined in authoritative guidance. Raw materials and purchased drug product associated with clinical development programs are included in inventory and charged to research and development expense when the product enters the research and development process and no longer can be used for commercial purposes and, therefore, does not have an “alternative future use”.
	Intangible Assets
	Intangible assets are recorded at acquisition cost less accumulated amortization and impairment. Intangible asset with finite lives are amortized over their estimated useful life using the economic use method, which reflects the pattern that the economic benefits of the intangible asset are consumed as revenue is generated. The pattern of consumption of the economic benefits is estimated using the future projected cash flows of the intangible asset.
	IPR&D
	The fair value of IPR&D acquired through a business combination is capitalized as an indefinite-lived intangible asset until the completion or abandonment of the related research and development activities. When the related research and development is completed, the asset is assigned a useful life and amortized.
	The fair value of an IPR&D intangible asset is determined using an income approach. This approach starts with a forecast of the net cash flows expected to be generated by the asset over its estimated useful life. The net cash flows reflect the asset’s stage of completion, the probability of technical success, the projected costs to complete, expected market competition, and an assessment of the asset’s life-cycle. The net cash flows are then adjusted to present value by applying an appropriate discount rate that reflects the risk factors associated with the cash flow streams.
	Goodwill
	Goodwill represents the excess of the purchase price of acquired businesses over the estimated fair value of the identifiable net assets acquired. Goodwill is not amortized but is tested for impairment at least annually at the reporting unit level or more frequently if events or changes in circumstances indicate that the asset might be impaired.
	Goodwill is tested for impairment annually or more frequently if events or changes in circumstances between annual tests indicate that the asset may be impaired. Impairment loss is recognized based on a comparison of the fair value of the asset to its carrying value, without consideration of any recoverability.
	Impairment of Long-lived Assets
	The Company reviews its property and equipment, intangible assets subject to amortization and other long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset class may not be recoverable. Indicators of potential impairment include: an adverse change in legal factors or in the business climate that could affect the value of the asset; an adverse change in the extent or manner in which the asset is used or is expected to be used, or in its physical condition; and current or forecasted operating or cash flow losses that demonstrate continuing losses associated with the use of the asset. If indicators of impairment are present, the asset is tested for recoverability by comparing the carrying value of the asset to the related estimated undiscounted future cash flows expected to be derived from the asset. If the expected cash flows are less than the carrying value of the asset, then the asset is considered to be impaired and its carrying value is written down to fair value, based on the related estimated discounted future cash flows.
	Indefinite-lived intangible assets, including acquired IPR&D, are tested for impairment annually or more frequently if events or changes in circumstances between annual tests indicate that the asset may be impaired. Impairment losses on indefinite-lived intangible assets are recognized based on a comparison of the fair value of the asset to its carrying value, without consideration of any recoverability.
	Acquisition-Related Contingent Consideration
	Acquisition-related contingent consideration, which consists primarily of potential milestone payments and royalty obligations, is recorded in the consolidated balance sheets at its acquisition date estimated fair value, in accordance with the acquisition method of accounting. The fair value of the acquisition-related contingent consideration is remeasured each reporting period, with changes in fair value recorded in the consolidated statements of operations. Changes in the fair value of the acquisition-related contingent consideration obligations result from several factors including changes in discount periods and rates, changes in the timing and amount of revenue estimates and changes in probability assumptions with respect to the likelihood of achieving specified milestone criteria. The fair value measurement is based on significant inputs not observable in the market and thus represents a Level 3 measurement as defined in the fair value hierarchy.
	Acquisition-Related Contingent Liability
	Acquisition-related contingent liability, which consists primarily of potential milestone payments and royalty obligations, and potential payments to certain employees of Andromeda is recorded in the consolidated balance sheets at its acquisition date estimated fair value. The Company reassesses the probability and estimates associated with the contingent liability at each reporting period. For liability payable to third parties, any increase in the liability is recorded in the consolidated statements of operations. For liabilities payable to employees, the Company accounts for the liability in accordance with Financial Accounting Stands Board (“FASB”) Accounting Stand Codification (“ASC”) 450 Contingencies.
	Property and Equipment
	Property and equipment are stated at cost, net of accumulated depreciation and amortization. All property and equipment is depreciated on a straight-line basis over the following estimated useful lives:


	Computer and office equipment			3 – 5 years
	Software			3 years
	Furniture and fixtures			3 years
	Leasehold improvements are amortized over the lesser of their useful life or the term of the applicable lease. Upon sale or retirement of assets, the cost and related accumulated depreciation and amortization are removed from the consolidated balance sheet and the resulting gain or loss is reflected in operations. Maintenance and repairs are charged to operations as incurred.

	2012 Reverse Stock Split
	The Company effected a 1-for-6.09 reverse stock split of its common stock and preferred stock on July 12, 2012. Accordingly, all share and per share amounts for all periods presented in these consolidated financial statements and notes thereto, have been adjusted retroactively to reflect this reverse stock split.
	Preclinical and Clinical Trial Accruals
	The Company’s clinical trial accruals are based on estimates of patient enrollment and related costs at clinical investigator sites as well as estimates for the services received and efforts expended pursuant to contracts with multiple research institutions and clinical research organizations that conduct and manage preclinical and clinical trials on the Company’s behalf. The Company accrues expenses related to clinical trials based on contracted amounts applied to the level of patient enrollment and activity according to the protocol. If timelines or contracts are modified based upon changes in the clinical trial protocol or scope of work to be performed, the Company modifies the estimates of accrued expenses accordingly. To date, the Company has had no significant adjustments to accrued preclinical and clinical trial expenses.
	Revenue Recognition
	The Company recognizes revenue in accordance with ASC 605, Revenue Recognition, when the following criteria have been met: persuasive evidence of an arrangement exists; delivery has occurred and risk of loss has passed; the seller’s price to the buyer is fixed or determinable and collectability is reasonably assured. The Company determines that persuasive evidence of an arrangement exists based on written contracts that defined the terms of the arrangements. In addition, the Company determines that services have been delivered in accordance with the arrangement. The Company assesses whether the fee is fixed or determinable based on the payment terms associated with the transaction and whether the sales price is subject to refund or adjustment. The Company assesses collectability based primarily on the customer’s payment history and on the creditworthiness of the customer.
	Product Revenue, net: The Company’s product revenue represents sales of RAVICTI and BUPHENYL which are recognized once all four revenue recognition criteria described above are met. The Company recognizes revenue net of product sales allowances. Product shipping and handling costs are included in cost of sales. Prior to June 2014, revenue from the sale of RAVICTI was recognized based on the amount of product sold through to the end user consumer. Starting June 2014, the Company could reasonably estimate and determine sales allowances, therefore the Company began recognizing RAVICTI revenue at the point of sale to the specialty distributor, which resulted in the one-time non-recurring recognition of an additional $8.6 million in net revenues during the year ended December 31, 2014. The impact of this change resulted in a decrease in net loss of $7.9 million for year ended December 31, 2014, or $0.39 per basic and diluted share.
	Product Sales Allowances: The Company establishes reserves for prompt-payment discounts, government and commercial rebates, product returns and chargebacks. Allowances relate to prompt-payment discounts and are recorded at the time of revenue recognition, resulting in a reduction in product sales revenue and a decrease in trade accounts receivables. Accruals related to government rebates, product returns and other applicable allowances such as distributor fees are recognized at the time of revenue recognition, resulting in a reduction in product sales and an increase in accrued expenses or a reduction in the related accounts receivable.

		•		Prompt-payment discounts: The specialty distributor and specialty pharmacies are offered prompt payment discounts. The Company expects the specialty distributor and specialty pharmacies will earn prompt payment discounts and, therefore deduct the full amount of these discounts from total product sales when revenues are recognized. The Company records prompt-payment discounts as allowances against accounts receivable on the consolidated balance sheets.

		•		Rebates: Allowances for rebates include mandated discounts under the Medicaid Drug Rebate Program. Rebate amounts are based upon contractual agreements or legal requirements with public sector (e.g. Medicaid) benefit providers. Rebates are amounts owed after the final dispensing of the product to a benefit plan participant and are based upon contractual agreements or legal requirements with public sector benefit providers. The allowance for rebates is based on statutory discount rates and expected utilization. The Company estimates for expected utilization of rebates based on historical data and data received from the specialty pharmacies. Rebates are generally invoiced and paid in arrears so that the accrual balance consists of an estimate of the amount expected to be incurred for the current quarter’s activity, plus an accrual balance for known prior quarter’s unpaid rebates. If actual future rebates vary from estimates, the Company may need to adjust prior period accruals, which would affect revenue in the period of adjustment. Allowance for rebates are recorded in accrued liabilities on the consolidated balance sheets.

		•		Chargebacks: Chargebacks are discounts that occur when contracted customers purchase directly from a specialty distributor. Contracted customers, which primarily consist of Public Health Service institutions, non-profit clinics, and Federal government entities purchasing via the Federal Supply Schedule, generally purchase the product at a discounted price. The specialty distributor, in turn, charges back to the Company the difference between the price initially paid by the specialty distributor and the discounted price paid to the specialty distributor by the customer. The allowance for chargebacks is based on historical sales data and known sales to contracted customers.

		•		Medicare Part D Coverage Gap: Medicare Part D prescription drug benefit mandates manufacturers to fund 50% of the Medicare Part D insurance coverage gap for prescription drugs sold to eligible patients. The Company estimates for the expected Medicare Part D coverage gap are based on historical invoices received and in part from data received from the specialty pharmacies. Funding of the coverage gap is generally invoiced and paid in arrears so that the accrual balance consists of an estimate of the amount expected to be incurred for the current quarter’s activity, plus an accrual balance for known prior quarters. If actual future funding varies from estimates, the Company may need to adjust prior period accruals, which would affect revenue in the period of adjustment. Estimates of the Medicare Part D coverage gap are recorded in accrued liabilities on the consolidated balance sheets.

		•		Distribution Service Fees: The Company has a written contract with the specialty distributor that includes terms for distribution-related fees. Distributor fees are calculated at percentage of gross sales based upon agreed contracted rate. The Company accrues distributor fees at the time of the revenue recognition, resulting in reduction of product sales revenue and the recording of accrued liabilities on the consolidated balance sheets. The Company records distribution and other fees paid to its customers as a reduction of revenue, unless it receives an identifiable and separate benefit for the consideration and it can reasonably estimate the fair value of the benefit received. If both conditions are met, the Company records the consideration paid to the customer as an operating expense. These costs are typically known at the time of sale.

	•		Product Returns: Consistent with industry practice, the Company generally offers customers a limited right to return. The Company accepts returns of products from patients resulting from breakage as defined within the Company’s returns policy. Additionally, the Company considers several other factors in the estimation process including the expiration dates of product shipped, third party data in monitoring channel inventory levels, shelf life of the product, prescription trends and other relevant factors. Provisions for estimated product returns are recorded as accrued liabilities on the consolidated balance sheets.

	•		Co-payment assistance: The Company provides a cash donation to a non-profit third party organization which supports patients, who have commercial insurance and meet certain financial eligibility requirements, with co-payment assistance and travel costs. The amount of co-payment assistance is accounted for by the Company as a reduction of revenues.
Cost of sales
Cost of sales includes third-party manufacturing cost of products sold, royalty fees, and other indirect costs related to personnel compensation, shipping and supplies. Costs incurred prior to FDA approval of RAVICTI have been recorded as research and development expense in the Company’s consolidated statement of operations. The Company expects that cost of RAVICTI sales as a percentage of revenue will increase in future periods as product manufactured prior to FDA approval, and therefore fully expensed, has been utilized. Cost of BUPHENYL sales for 2013 as a percentage of revenue was higher and not indicative of cost of sales in future periods due to the recording of the step-up value on BUPHENYL inventories acquired from Ucyclyd which is expensed to cost of sales as that inventory is sold. As of December 31, 2014, the entire fair value of acquired BUPHENYL inventory has been charged to expense, primarily cost of sales.
Foreign Currency Translations
Operations in non-U.S. entities are recorded in the functional currency of each entity. For financial reporting purposes, the functional currency of an entity is determined by a review of the source of an entity’s most predominant cash flows. The reporting and functional currency of the Company and its subsidiaries is the U.S. dollar.
Gains and losses resulting from foreign currency transactions are translated at the weighted average rate of exchange prevailing during the period. Any monetary asset or liability denominated in foreign currency and is translated at the rate of exchange in effect on the balance sheet date. Any gains and losses resulting from foreign currency translations are included in other income (expense)-net in the consolidated statements of operations. The Company does not currently utilize and has not in the past utilized any foreign currency hedging strategies to mitigate the effect of its foreign currency exposure.
Research and Development Expenses
Costs related to research and development of products are charged to expense as incurred. Research and development costs include, but are not limited to, payroll and personnel expenses, clinical trial supplies, fees for clinical trial services, consulting costs and allocated overhead, including rent, equipment, depreciation and utilities.
Stock-Based Compensation
The Company accounts for stock-based employee compensation arrangements in accordance with provisions of ASC 718, Compensation — Stock Compensation. ASC 718 requires the recognition of compensation expense, using a fair-value based method, for costs related to all share-based payments including stock options. ASC 718 requires companies to estimate the fair value of share-based payment awards on the date of grant using an option-pricing model. The Company calculates the fair value of stock options using the Black-Scholes method and expenses using the straight-line attribution approach.
Income Taxes
The Company accounts for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized.
The Company accounts for uncertain tax positions in accordance with ASC 740-10, Accounting for Uncertainty in Income Taxes. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the position’s sustainability and is measured at the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. As of each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized tax benefit is still appropriate. The recognition and measurement of tax benefits requires significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available.
Comprehensive Income (Loss)
Comprehensive income (loss) is comprised of net income (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.
Net Income (Loss) per Share of Common Stock
Basic earnings per share is computed by dividing the net income (loss) by the weighted average number of shares of common stock outstanding during the periods presented. The computation of diluted earnings per share is similar to the computation of basic earnings per share, except that the denominator is increased for the assumed exercise of dilutive options and other potentially dilutive securities using the treasury stock method, unless the effect is antidilutive.
Recent Accounting Pronouncements
In July 2013, FASB issued ASU No. 2013-11, Income Taxes (Topic 740): Presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. Under the amendments of this update an entity is required to present an unrecognized tax benefit, or a portion of an unrecognized tax benefit in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except as follows. To the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position or the tax law of the applicable jurisdiction does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. The assessment of whether a deferred tax asset is available is based on the unrecognized tax benefit and deferred tax asset that exist at the reporting date and should be made presuming disallowance of the tax position at the reporting date. For example, an entity should not evaluate whether the deferred tax asset expires before the statute of limitations on the tax position or whether the deferred tax asset may be used prior to the unrecognized tax benefits being settled. The provisions of this update was effective prospectively for the Company in fiscal years beginning after December 15, 2013 with early adoption and retrospective application permitted. The Company adopted this guidance on January 1, 2014. The implementation did not have an impact on the Company’s consolidated financial statements.
In May 2014, FASB issued Accounting Standards Update 2014-09 (ASU 2014-09), Revenue from Contracts with Customers. ASU 2014-09 will supersede the revenue recognition requirements in Revenue Recognition (Topic 605) and requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period, which for the Company is January 1, 2017. Early adoption is not permitted. The Company is currently evaluating the potential impact the adoption of ASU 2014-09 will have on the Company’s consolidated financial statements.

Collaboration_Agreement_with_U

Collaboration Agreement with Ucyclyd Pharma, Inc.	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Collaboration Agreement with Ucyclyd Pharma, Inc.	3	Collaboration Agreement with Ucyclyd Pharma, Inc.
	In March 2012, the Company entered into the purchase agreement with Ucyclyd under which the Company purchased the worldwide rights to RAVICTI and the amended and restated collaboration agreement (the “restated collaboration agreement”) under which Ucyclyd granted the Company an option to purchase all of Ucyclyd’s worldwide rights to BUPHENYL and AMMONUL at a fixed price at a future defined date, plus subsequent milestone and royalty payments, subject to Ucyclyd’s right to retain AMMONUL for a predefined price. The restated collaboration agreement superseded the collaboration agreement with Ucyclyd, dated August 23, 2007, as amended. The entry into the purchase agreement and the restated collaboration agreement resolved a dispute that the two parties had with respect to their rights under the prior collaboration agreement.
	Under the purchase agreement, the Company made a payment of $6.0 million of which (i) $5.7 million was allocated to the worldwide rights to RAVICTI and (ii) $0.3 million was allocated to the option to purchase rights to BUPHENYL and AMMONUL, based on their relative fair values. The allocated amount to the rights to RAVICTI of $5.7 million was recorded to research and development expense in the consolidated statements of operations for the period ended March 31, 2012 due to the uncertainty of an alternative future use. The allocated amount for the option to purchase rights to BUPHENYL and AMMONUL in the amount of $0.3 million was included within other current assets and was subsequently offset against the gain recognized from the settlement of retention option (see Note 4).
	The Company will also pay tiered mid to high single digit royalties on global net sales of RAVICTI and may owe regulatory milestones of up to $15.8 million related to approval of GPB in HE, regulatory milestones of up to $7.3 million per indication for approval of GPB in indications other than UCD or HE, and net sales milestones of up to $38.8 million if GPB is approved for use in indications other than UCD (such as HE) and all annual sales targets are reached.
	In addition, the intellectual property license agreements executed between Ucyclyd and Dr. Marshall L. Summar, (“Summar”) and Ucyclyd and Brusilow Enterprises, LLC, (“Brusilow”) were assigned to the Company, and the Company has assumed the royalty and milestone obligations under the Brusilow agreement for sales of RAVICTI in any indication and the royalty obligations under the Summar agreement on sales of GPB to treat HE. The Brusilow and Summar agreements provide that royalty obligations will continue, without adjustment, even if generic versions of the licensed products are introduced and sold in the relevant country.
	Under the terms of the restated collaboration agreement, the Company had an option to purchase all of Ucyclyd’s worldwide rights in BUPHENYL and AMMONUL, subject to Ucyclyd’s option to retain rights to AMMONUL. The Company was permitted to exercise this option for 90 days beginning on the earlier of the date of the approval of RAVICTI for the treatment of UCD and June 30, 2013, but in no event earlier than January 1, 2013. The upfront purchase price for AMMONUL and BUPHENYL was $22.0 million. If the RAVICTI New Drug Application (“NDA”) for UCD was not approved by January 1, 2013, then Ucyclyd was obligated to make monthly payments of $0.5 million to the Company until the earliest of (1) FDA approval of the RAVICTI NDA for UCD, (2) June 30, 2013 and (3) the Company’s written notification of the decision not to purchase Ucyclyd’s worldwide rights to BUPHENYL and AMMONUL.
	On February 1, 2013, the FDA approved RAVICTI for the treatment of UCD in adult and pediatric patients two years of age and older. In accordance with the restated collaboration agreement, Ucyclyd made a payment of $0.5 million during the quarter ended March 31, 2013.
	On April 29, 2013, the Company exercised its option to purchase BUPHENYL and AMMONUL. Ucyclyd subsequently exercised it’s time-limited right to elect to retain all rights to AMMONUL for a contractual purchase price of $32.0 million (“retention amount”). Upon closing of the transaction, Ucyclyd paid the Company a net payment of $11.0 million, which reflects the Company’s contractual purchase price for Ucyclyd’s worldwide rights to BUPHENYL in the amount of $19.0 million being off-set against Ucyclyd’s retention amount for AMMONUL and a $2.0 million payment due to Ucyclyd for inventory that the Company purchased from Ucyclyd. The Company has retained a right of first negotiation should Ucyclyd later decide to sell, exclusively license, or otherwise transfer the AMMONUL assets to a third party.
	On May 31, 2013, the Company completed the acquisition of BUPHENYL. Upon Ucyclyd’s exercise of its retention option, the Company recorded a gain of approximately $31.1 million in its consolidated statement of operations. The amount of gain is comprised of (i) fair value of BUPHENYL of $20.4 million and (ii) net cash received from Ucyclyd of $11.0 million off-set by (iii) the $0.3 million carrying value of the option to purchase the rights to BUPHENYL and AMMONUL.

Acquisitions

12 Months Ended

Dec. 31, 2014

Business Combinations [Abstract]

Acquisitions

Acquisition of Andromeda

Description of the Transaction

On April 23, 2014, Hyperion Therapeutics Israel Holding Corp. Ltd. (“Hyperion Israel”), a wholly-owned subsidiary of the Company entered into a share purchase agreement (“SPA”) with Clal Biotechnology Industries Ltd. (“Clal”) to purchase all outstanding shares of Andromeda. Andromeda was incorporated in Israel in 2007 and was primarily focused on the development of DiaPep277.

On June 12, 2014 (the “Acquisition Date”), Hyperion Israel completed the purchase of all of the outstanding ordinary shares of Andromeda. The Andromeda acquisition is accounted for as a business combination. The results of operations of Andromeda have been included in the Company’s consolidated statements of operations starting from the Acquisition Date, the date on which the Company obtained effective control of Andromeda.

Fair Value of Consideration Transferred as of the Acquisition Date

The Company accounted for the acquisition of Andromeda as a business combination under the acquisition method of accounting. The Acquisition Date fair value of the total consideration transferred to acquire Andromeda was as follows:

Amounts Recognized as

of the acquisition date

(in thousands)

Cash paid

14,345

Fair value of Company’s common stock issued (312,869 shares)

7,778

Acquisition-related contingent consideration

68,961

Total fair value of consideration transferred

91,084

The fair value of the common stock was measured using the Company’s closing stock price on June 12, 2014.

The Company estimated the fair value of the acquisition-related contingent consideration on the acquisition date using a probability-weighted income approach, which reflects the probability and timing of future payments. This fair value measurement on the acquisition date is based on key assumptions such as the anticipated timelines and probability of achieving development, regulatory approval or sales-based milestone events and projected revenues. The resulting probability-weighted cash flows are discounted using estimated discount rate that commensurate with the risks of the expected cash flows attributable to the various milestones. The material factors that may impact the fair value are the probabilities of achieving the related milestones and the discount rate. Significant increases or decreases in any of the probabilities of success would result in a significantly higher or lower fair value, respectively, and commensurate changes to this liability. The fair value relating to the acquisition-related contingent consideration at each reporting date will be updated with the changes in fair value reflected in the company’s consolidated statements of operations.

Assets Acquired and Liabilities Assumed as of the Acquisition Date

The following table summarizes the provisional allocation of purchase price to the fair values of the assets acquired and liabilities assumed as of the acquisition date:

Amounts Recognized as

of the acquisition date

(in thousands)

Assets acquired

IPR&D

135,712

Cash and cash equivalents

306

Prepaid expenses

Property and equipment, net

Other assets

578

Liabilities assumed

Current liabilities

(9,079

)

Deferred tax liability

(6,051

)

Acquisition related contingent liability

(34,288

)

Total identifiable net assets

87,295

Goodwill

3,789

Total consideration transferred

91,084

The amounts were considered preliminary and were subject to change once the Company finalizes the determination of the fair value of assets acquired and liabilities assumed. Thus, these amounts were subject to refinement and final determination of the fair values of net assets acquired and may result in certain adjustments to the amounts presented above.

The contingent liabilities amounting to $34.3 million relate to potential royalties and milestone payments and potential payments. The Company reassesses the probability and estimates associated with the contingent liability at each reporting period. For liability payable to third parties, any increase in the liability is recorded in the consolidated statements of operations. For liabilities payable to employees in exchange for services, the Company accounts for this liability arrangement as employee compensation over the applicable service period and in accordance with ASC 450 Contingencies.

The goodwill primarily represents the tax impact of the IPR&D and acquisition related contingencies as well as acquiring Andromeda’s assembled workforce.

Measurement period adjustments to provisional allocation of purchase price

On September 8, 2014 the Company announced the termination of further development of DiaPep277 beyond completion of the ongoing clinical trial as a result of evidence that the Company uncovered that certain employees of Andromeda engaged in serious misconduct that compromised clinical trial results. Additional evidence indicates that the biostatistics firm and certain Andromeda employees continued the improper practice of sharing and examining un-blinded data from the ongoing DIA-AID 2 trial. The Company intends to complete the ongoing Phase 3 clinical trial of DiaPep277 but does not expect to develop the product further.

The Company determined that the facts and circumstances described above existed as of the acquisition date and were not the result of intervening events subsequent to the acquisition date. In accordance with ASC 805, during the measurement period, the Company recognizes adjustments to the provisional amounts as if the accounting for the business combination had been completed at the acquisition date. Accordingly, the Company re-measured the preliminary determination of the fair values of assets acquired and liabilities assumed as of the acquisition date. The measurement period adjustments primarily relate to the: (i) decrease in the estimated fair value of intangible assets, (ii) reductions in the acquisition related contingent liability, and (iii) the tax impact of pre-tax measurement period adjustments.

Adjusted Assets Acquired and Liabilities Assumed — Measurement Period Adjustments

The following table summarizes the adjusted provisional allocation of purchase price to the fair values of the assets acquired and liabilities assumed as of the Acquisition Date:

Amounts Recognized

as of September 30,

2014 (as adjusted)

(in thousands)

Assets acquired

IPR&D

—

Cash and cash equivalents

306

Prepaid expenses

Property and equipment, net

Other assets

578

Liabilities assumed

Current liabilities

(9,079

)

Deferred tax liability

—

Acquisition related contingent liability

—

Total identifiable net assets (liabilities)

(8,078

)

Adjusted Goodwill

30,201

Total consideration transferred

22,123

Adjusted Fair Value of Consideration Transferred

Amounts Recognized

as of September 30,

2014 (as adjusted)

(in thousands)

Cash paid

14,345

Fair value of Company’s common stock issued (312,869 shares)

7,778

Acquisition-related contingent consideration

—

Total fair value of consideration transferred

22,123

The Company has assigned no value to the IPR&D as a result of the evidence obtained related to the improper practices regarding the clinical trials. The Company had determined that the contingent consideration milestones and contingent liability milestones will not be achieved.

The reduction in deferred tax liability relates to the tax impact of the IPR&D and acquisition- related contingencies.

The Company’s allocation of purchase price to the fair values of the assets acquired and liabilities assumed as of acquisition date was determined to be final as the Company obtained the information necessary to complete the measurement process.

Acquisition of BUPHENYL from Ucyclyd Pharma, Inc.

Description of the Transaction

As discussed in Note 3, under the terms of the restated collaboration agreement, on April 29, 2013, the Company exercised its option to purchase all of Ucyclyd’s worldwide rights in BUPHENYL and AMMONUL. On May 17, 2013 Ucyclyd exercised its time-limited right to elect to retain all rights to AMMONUL. On May 31, 2013 (the “Acquisition Date”), the Company completed the acquisition of BUPHENYL. Accordingly, BUPHENYL results are included in Hyperion’s consolidated financial statements from the date of the acquisition. For the period from June 1, 2013 to December 31, 2013, BUPHENYL net revenue was $11.5 million.

The Company acquired BUPHENYL to enhance its commercial product portfolio and to allow the Company an opportunity to serve the entire UCD patient population, including those less than two years of age or for those patients who may prefer BUPHENYL.

Purchase Consideration and Assets Acquired

The Company accounted for the acquisition of BUPHENYL as a business combination under the acquisition method of accounting. On the Acquisition Date, the Company received a net payment of $11.0 million, which reflected the $32.0 million retention amount for AMMONUL due to the Company less the $19.0 million contractual purchase price for BUPHENYL due to Ucyclyd and a $2.0 million payment due to Ucyclyd for inventory that the Company purchased from Ucyclyd.

The fair value of purchase consideration was estimated based upon the fair value of assets acquired. The estimated fair value attributed to the BUPHENYL product rights was determined on a discounted forecast of the estimated net future cash flows to be generated from the product rights and has an expected useful life of 10 years. The following table summarizes the allocation of purchase price to the fair values of the assets acquired as of the acquisition date:

(in thousands)

Inventories

3,900

Intangible Asset — BUPHENYL Product rights

16,500

Total

20,400

Gain from Settlement of Retention Option

In connection with the allocation between the BUPHENYL acquisition described above and Ucyclyd’s exercise of its retention option, the Company recorded a gain of $31.1 million. The amount of gain is comprised of (i) fair value of BUPHENYL of $20.4 million and (ii) net cash received from Ucyclyd of $11.0 million off-set by (iii) the $0.3 million carrying value of the option to purchase the rights to BUPHENYL and AMMONUL. The following table summarizes the results of the Company’s allocation:

(in thousands)

Ucyclyd’s retention option amount

32,000

Amount due to Ucyclyd for BUPHENYL product rights

(19,000

)

Amount due to Ucyclyd for inventory

(2,038

)

Net payment received from Ucyclyd

10,962

Option to purchase the rights to BUPHENYL and AMMONUL

(283

)

Fair value of BUPHENYL

20,400

Gain from settlement of retention option

31,079

Pro forma Impact of Business Combination

The following unaudited pro forma information is based on the assumption that the Andromeda acquisition occurred on January 1, 2013 and BUPHENYL acquisition occurred on January 1, 2012. The unaudited pro forma information is presented for comparative purposes only and is not necessarily indicative of the financial position or results of operations which would have been reported had the Company completed the acquisitions during these periods or which might be reported in the future. The unaudited pro forma information reflects primarily the application of the following adjustments:

•

the elimination of the historical research and development expenses and general and administration expenses related to options granted to employees which were cancelled as part of the Andromeda acquisition;

•

the elimination of the historical interest expenses related to loans provided by former shareholders which were cancelled as part of the Andromeda acquisition;

•

the exclusion of acquisition-related costs incurred for the acquisitions;

•

the exclusion of impairment of goodwill recognized in relation to the Andromeda acquisition;

•

the inclusion of amortization expense related to the fair value of the intangible asset acquired relating to BUPHENYL;

•

the inclusion of the step-up value related to inventory sold that was acquired as part of the BUPHENYL acquisition. Such amounts are included in the applicable comparative period for purposes of pro forma financial information; and

•

as noted above, the Company issued 312,869 shares of its common stock as part of the Andromeda acquisition. The common shares were included in the pro-forma earnings per share calculation.

The unaudited pro forma information is not necessarily indicative of what the Company’s consolidated results of operations actually would have been had the acquisition of Andromeda been completed on January 1, 2013 and acquisition of BUPHENYL been completed on January 1, 2012. In addition, the unaudited pro forma information does not purport to project the future results of operations of the Company.

Year Ended

December 31,

2014

2013

2012

( in thousands)

Net revenues

113,584

52,900

21,501

Net income (loss)

20,390

(12,199

)

(29,201

)

Net income (loss) per common share

Basic

0.99

(0.62

)

(4.02

)

Diluted

0.93

(0.62

)

(4.02

)

Acquisition-related Costs

Acquisition-related expenses consist of transaction costs which represent external costs directly related to the acquisition of Andromeda and primarily include expenditures for professional fees such as legal, accounting and other directly related incremental costs incurred to close the acquisition. Acquisition-related expenses for the year ended December 31, 2014 was $1.3 million. Acquisition-related expenses for the year ended December 31, 2013 were $0.6 million. These expenses were recorded to selling and general administrative expense in the consolidated statements of operations.

Investments

Investments	12 Months Ended
Investments	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Investments	5	Investments
	All investments were classified as available-for-sale at December 31, 2014 and December 31, 2013. The principal amounts of investments by contractual maturity at December 31, 2014 and December 31, 2013 are summarized in the tables below:


			Contractual Maturity Date for the					Total Book		Unrealized			Aggregate
			Years Ending December 31,					Value at		Loss			Fair Value at
								December 31, 2014					December 31, 2014
			2015		2016
	Certificates of deposit		$	18,405	$	6,240		$	24,645	$	(35	)	$	24,610
	Corporate notes			12,613		3,011			15,624		(12	)		15,612
	Commercial paper			3,494		—			3,494		(3	)		3,491

	Total		$	34,512	$	9,251		$	43,763	$	(50	)	$	43,713



			Contractual Maturity Date for the					Total Book		Unrealized			Aggregate
			Years Ending December 31,					Value at		Loss			Fair Value at
								December 31, 2013					December 31, 2013
			2014		2015
	Certificates of deposit		$	10,525	$	2,845		$	13,370	$	(27	)	$	13,343
	Corporate notes			6,047		12,960			19,007		(24	)		18,983
	U.S. Government agency securities			8,011		—			8,011		(3	)		8,008
	Commercial paper			3,492		—			3,492		(1	)		3,491

	Total		$	28,075	$	15,805		$	43,880	$	(55	)	$	43,825

	The Company evaluated its investments and determined that there were no other-than-temporary impairments as of December 31, 2014.
	The aggregate amounts of unrealized losses and related fair value of investments with unrealized losses as of December 31, 2014 and December 31, 2013 was as follows:


			Less Than 12 Months to					12 Months or More to					Total at December 31, 2014
			Maturity					Maturity					Total at December 31, 2014
			Aggregate		Unrealized			Aggregate		Unrealized			Aggregate		Unrealized
			Fair Value		Losses			Fair Value		Losses			Fair Value		Losses
	Certificates of deposit		$	18,386	$	(19	)	$	6,224	$	(16	)	$	24,610	$	(35	)
	Corporate notes			12,610		(2	)		3,002		(10	)		15,612		(12	)
	Commercial paper			3,491		(3	)		—		—			3,491		(3	)

	Total		$	34,487	$	(24	)	$	9,226	$	(26	)	$	43,713	$	(50	)



			Less Than 12 Months to					12 Months or More to					Total at December 31, 2013
			Maturity					Maturity					Total at December 31, 2013
			Aggregate		Unrealized			Aggregate		Unrealized			Aggregate		Unrealized
			Fair Value		Losses			Fair Value		Losses			Fair Value		Losses
	Certificates of deposit		$	10,507	$	(18	)	$	2,836	$	(9	)	$	13,343	$	(27	)
	Corporate notes			6,039		(8	)		12,944		(16	)		18,983		(24	)
	U.S. Government agency securities			8,008		(3	)		—		—			8,008		(3	)
	Commercial paper			3,491		(1	)		—		—			3,491		(1	)

	Total		$	28,045	$	(30	)	$	15,780	$	(25	)	$	43,825	$	(55	)

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Measurements	6	Fair Value Measurements
	The Company follows ASC 820-10, “Fair Value Measurements and Disclosures,” which among other things, defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, a three-tier fair value hierarchy has been established, which prioritizes the inputs used in measuring fair value as follows:

		•		Level 1 — Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date.

		•		Level 2 — Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life.

		•		Level 3 — Inputs reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model.
	The following table presents the Company’s fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of December 31, 2014 and December 31, 2013 (in thousands):


			Fair Value Measurements at December 31, 2014
			Quoted Price in			Significant Other			Significant			Total
			Active Markets			Observable Inputs			Unobservable
			for Identical Assets			(Level 2)			Inputs
			(Level 1)						(Level 3)
	Assets:
	Cash equivalents:
	Money market funds		$	38,532		$	—		$	—		$	38,532
	Certificates of deposit			—			720			—			720

	Total cash equivalents		$	38,532		$	720		$	—		$	39,252

	Available-for-sale securities:
	Short-term:
	Certificates of deposit		$	—		$	18,386		$	—		$	18,386
	Corporate notes			—			12,610			—			12,610
	Commercial paper			—			3,491			—			3,491

	Total short-term investments			—			34,487			—			34,487

	Long-term:
	Certificates of deposit			—			6,224			—			6,224
	Corporate notes			—			3,002			—			3,002

	Total long-term investments			—			9,226			—			9,226

	Total available-for-sale securities		$	—		$	43,713		$	—		$	43,713



			Fair Value Measurements at December 31, 2013
			Quoted Price in			Significant Other			Significant			Total
			Active Markets			Observable Inputs			Unobservable
			for Identical Assets			(Level 2)			Inputs
			(Level 1)						(Level 3)
	Assets:
	Cash equivalents:
	Money market funds		$	38,506		$	—		$	—		$	38,506
	Certificates of deposit			—			480			—			480

	Total cash equivalents		$	38,506		$	480		$	—		$	38,986

	Available-for-sale securities:
	Short-term:
	Certificates of deposit		$	—		$	10,507		$	—		$	10,507
	Commercial paper			—			3,491			—			3,491
	Corporate notes			—			6,039			—			6,039
	U.S. Government agency securities			—			8,008			—			8,008

	Total short-term investments			—			28,045			—			28,045

	Long-term:
	Certificates of deposit			—			2,836			—			2,836
Corporate notes			—			12,944			—			12,944

Total long-term investments			—			15,780			—			15,780

Total available-for-sale securities		$	—		$	43,825		$	—		$	43,825

The following table presents the carrying value and estimated fair value of the Company’s notes payable as of December 31, 2014 and December 31, 2013 (in thousands):


		December 31, 2014
		Carrying			Estimated
		Value			Fair Value
Term Loans (see Note 11)		$	16,124		$	16,746


		December 31, 2013
		Carrying			Estimated
		Value			Fair Value
April and September 2012 Notes (see Note 11)		$	8,273		$	8,860
Valuation Techniques
Level 1 Inputs
The Company classifies money market funds, which are valued based on quoted market prices in active markets with no valuation adjustment, as Level 1 assets within the fair value hierarchy.
Level 2 Inputs
Items classified as Level 2 within the valuation hierarchy consist of commercial paper, corporate notes, U.S. government agency securities and certificates of deposit. The Company estimates the fair values of these marketable securities by taking into consideration valuations obtained from third-party pricing sources. These pricing sources utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include market pricing based on real-time trade data for the same or similar securities, issuer credit spreads, benchmark yields, and other observable inputs. The Company validates the prices provided by our third-party pricing sources by obtaining market values from other pricing sources and analyzing pricing data in certain instances.
Level 3 Inputs
Notes Payable
The Company has determined that its notes payable would be classified as a Level 3 item in the fair value hierarchy. The fair value of these notes is based on the present value of expected future cash flows and assumptions about current interest rates and the credit worthiness of the Company.
Acquisition-related Contingent Consideration and Liabilities
In connection with the acquisition of Andromeda, the Company may be required to pay future consideration that is contingent upon the achievement of specified development, regulatory approval or sales-based milestone events. The Company estimates the fair value of the contingent consideration liabilities on the acquisition date and each reporting period thereafter using a probability-weighted income approach, which reflects the probability and timing of future payments. This fair value measurement is based on significant Level 3 inputs such as the anticipated timelines and probability of achieving development, regulatory approval or sales-based milestone events and projected revenues. The resulting probability-weighted cash flows are discounted using estimated discount rate that commensurate with the risks of the expected cash flows attributable to the various milestones.
Each reporting period thereafter, the Company revalues these obligations by performing a review of the assumptions listed above and record increases or decreases in the fair value of these contingent consideration obligations in changes in fair value of contingent consideration expenses within the consolidated statements of operations until such time that the related product candidate receives marketing approval. In the absence of any significant changes in key assumptions, the quarterly determination of fair values of these contingent consideration obligations would primarily reflect the passage of time.
Updates to assumptions could have a significant impact on our results of operations in any given period and actual results may differ from estimates. For example, significant increases in the probability of achieving a milestone or projected revenues would result in a significantly higher fair value measurement while significant decreases in the estimated probability of achieving a milestone or projected revenues would result in a significantly lower fair value measurement. Significant increases in the discount rate or in the anticipated timelines would result in a significantly lower fair value measurement while significant decreases in the discount rate or anticipated timelines would result in a significantly higher fair value measurement.
As discussed in Note 4, the Company re-measured the preliminary determination of the fair values of assets acquired and liabilities assumed as of the acquisition date. The Company had determined that the contingent consideration milestones and contingent liability milestones will not be achieved.

Inventories

Inventories	12 Months Ended
Inventories	Dec. 31, 2014
Inventory Disclosure [Abstract]
Inventories	7	Inventories
	The following table represents the components of inventories, net of reserves (in thousands):


			December 31,		December 31,
			2014		2013
	Raw Materials		$	1,787	$	697
	Work-in-process			543		—
	Finished goods			2,291		2,816

	Total		$	4,621	$	3,513

	Reserves on the inventory balance was $0.3 million for the year ended December 31, 2014. There were no reserves for the year ended December 31, 2013.

Intangible_Assets_and_Goodwill

Intangible Assets and Goodwill	12 Months Ended
Intangible Assets and Goodwill	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	8	Intangible Assets and Goodwill
	Finite lived intangible asset
	In May 2013, the Company acquired BUPHENYL and as part of this transaction, the Company recognized $16.5 million of an intangible asset relating to BUPHENYL product rights. The intangible asset is amortized over the estimated useful life using the economic use method, which reflects the pattern that the economic benefit of the intangible asset is consumed as revenue is generated. The pattern of consumption of the economic benefit is estimated using the future projected cash flow of the intangible asset which is reviewed on a regular basis. The Company estimated the useful life of the BUPHENYL product rights to be 10 years. The weighted average life remaining as of December 31, 2014 is 8.0 years.
	Intangible asset amortization expense was $4.6 million and $3.1 million for the years ended December 31, 2014 and 2013, respectively.
	Estimated aggregate amortization expense for each of the five succeeding years ending December 31 is as follows (in thousands):


			2015		2016		2017		2018		2019
	Amortization expense		$	6,495	$	1,655	$	1,515	$	1,477	$	1,441
	Goodwill
	As discussed in Note 4, in June 2014, the Company acquired Andromeda and as part of this transaction, the Company recognized goodwill in the amount of $30.2 million. The Company does not amortize goodwill but tests goodwill for impairment on an annual basis and in between annual tests if the Company becomes aware of any events or changes in circumstances that would more likely than not indicate a reduction in the fair value of a reporting unit below its carrying amount. Due to the Company’s decision to terminate the development of Diapep277, the Company determined that sufficient indicators of potential impairment existed to require an interim goodwill impairment analysis.
	The impairment test for goodwill is a two-step process. Step one consists of a comparison of the fair value of a reporting unit against its carrying amount, including the goodwill allocated to each reporting unit. The Company determines the fair value of the reporting unit based on the present value of estimated future cash flows as well as various price or market multiples applied to the reporting unit’s operating results, which are classified as level 3 within the fair value hierarchy (as described in Note 6). If the carrying amount of the reporting unit is in excess of its fair value, step two requires the comparison of the implied fair value of the reporting unit’s goodwill against the carrying amount of the reporting unit’s goodwill. Any excess of the carrying value of the reporting unit’s goodwill over the implied fair value of the reporting unit’s goodwill is recorded as an impairment loss.
	For the evaluation of the goodwill, management considered Andromeda to be a reporting unit and assigned no value to the Andromeda reporting unit. The Company also determined that the implied fair value of goodwill is zero. Thus, the excess of the carrying amount of goodwill over the implied fair value of the Andromeda reporting unit of $30.2 million was recorded as an impairment loss in the Company’s consolidated statements of operations for the year ended December 31, 2014.

Property_and_Equipment

Property and Equipment	12 Months Ended
Property and Equipment	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property and Equipment	9	Property and Equipment
	The following table represents the components of property and equipment (in thousands):


			December 31,
			2014			2013
	Computers and Software		$	1,202		$	563
	Furniture and Fixtures			320			320
	Office Equipment			53			53
	Leasehold Improvements			—			—
	Capital work in progress			181			264

				1,756			1,200
	Less: Accumulated depreciation			(640	)		(264	)

	Total property and equipment, net		$	1,116		$	936

	Depreciation expense for the years ended December 31, 2014, 2013 and 2012 was $0.5 million, $0.2 million and $15,000, respectively.

Accrued_Liabilities

Accrued Liabilities	12 Months Ended
Accrued Liabilities	Dec. 31, 2014
Payables and Accruals [Abstract]
Accrued Liabilities	10	Accrued Liabilities
	The following table represents the components of accrued liabilities (in thousands):


			December 31,
			2014		2013
	Clinical trial expenses		$	2,399	$	246
	Payroll and related expenses			4,134		4,278
	Gross to net sales accruals			10,142		5,235
	Royalty payable			2,080		1,154
	Taxes payable			563		326
	Legal expenses payable			410		45
	Acquisition related accrual (Note 22)			4,615		—
	Other			1,166		903

			$	25,509	$	12,187

Notes_Payable

Notes Payable	12 Months Ended
Notes Payable	Dec. 31, 2014
Debt Disclosure [Abstract]
Notes Payable	11	Notes Payable
	April 2011 Convertible Notes Payable
	In April 2011, the Company entered into a convertible notes financing (the “April 2011 convertible notes financing”), in which it issued an aggregate principal amount of $17.5 million of convertible notes in an initial closing in April and an aggregate principal amount of $8,285 of convertible notes in subsequent closings in May 2011 (collectively, the “April 2011 Notes”) pursuant to the Convertible Note and Warrant Purchase Agreement dated April 1, 2011 (the “April 2011 Purchase Agreement”). The April 2011 Purchase Agreement permits the Company to issue up to an aggregate principal amount of $35.0 million.
	The April 2011 Notes accrue interest at a rate of 6% per annum and have a maturity date of the earliest of (i) demand by the holders of 66% of the principal amount of the then-outstanding April 2011 Notes under certain circumstances, which demand may not be made earlier than December 31, 2012, as amended or (ii) an event of default. The April 2011 Notes cannot be prepaid, except on demand by the holders of the April 2011 Notes, as described above. The principal and the interest under the April 2011 Notes are automatically convertible (i) into securities that are sold in an issuance of preferred stock generating gross proceeds of at least $30.0 million, referred to herein as a qualified financing, at the lowest price at which such securities are sold to certain new investors in the qualified financing, (ii) into Series C-2 convertible preferred stock upon the occurrence of certain change of control events, unless the holders of 66% of the principal amount of the then-outstanding April 2011 Notes notify the Company of their election to accelerate the unpaid principal and interest of the April 2011 Notes in connection with the change of control event, or (iii) into common stock immediately prior to the consummation of an initial public offering, at a conversion price equal to the initial public offering price. In addition, holders of 66% of the principal amount of the then-outstanding April 2011 Notes have the option to convert the April 2011 Notes (i) in the event that the Company consummates an equity financing that is not a “qualified financing,” as described above, prior to the maturity of the April 2011 Notes, into the equity securities issued in the equity financing, or (ii) upon maturity of the April 2011 Notes, if the April 2011 Notes have not been previously converted, into shares of the Company’s Series C-2 convertible preferred stock.
	On July 31, 2012, upon closing of the IPO, the principal and accrued interest under the Company’s April 2011 Notes amounting to $18.9 million converted into 1,888,054 shares of common stock. The carrying value, including the impact of the amendment to the April 2011 Notes as discussed below and accrued interest under the Company’s April 2011 Notes was $18.4 million as of July 31, 2012.
	October 2011 Convertible Notes Payable
	In October 2011, the Company entered into a convertible notes financing (the “October 2011 convertible notes financing”), in which it issued an aggregate principal amount of $7.5 million of convertible notes in an initial closing in October and an aggregate principal amount of $3,551 of convertible notes in a subsequent initial closing in November 2011 and aggregate amount of $7.5 million of convertible notes in the second closing in February 2012 (collectively, the “October 2011 Notes”) pursuant to the Convertible Note and Warrant Purchase Agreement dated October 26, 2011 (the “October 2011 Purchase Agreement”). The October 2011 Purchase Agreement permitted the Company to issue up to an aggregate principal amount of $15.0 million.
	The October 2011 Notes accrue interest at a rate of 6% per annum and have a maturity date of the earliest of (i) demand by the holders of 66% of the principal amount of the then-outstanding October 2011 Notes under certain circumstances, which demand may not be made earlier than December 31, 2012, or (ii) an event of default. The October 2011 Notes cannot be prepaid, except on demand by the holders of the October 2011 Notes, as described above. The principal and the interest under the October 2011 Notes are automatically convertible (a) into securities that are sold in an issuance of preferred stock generating gross proceeds of at least $40.0 million, referred to herein as a qualified financing, equal to the quotient of (i) the outstanding principal amount plus unpaid accrued interest divided by (ii) the price per share paid by the investors purchasing new preferred stock in the qualified financing; (b) upon the occurrence of certain change in control events, into new series of preferred stock equal to the quotient of (i) the outstanding principal amount plus accrued interest divided by (ii) the Series C-2 original issue price, or (c) into common stock immediately prior to the consummation of an initial public offering, at a conversion price equal to the initial public offering price. In addition, holders of 66% of the principal amount of the then-outstanding October 2011 Notes have the option to convert the October 2011 Notes (i) in the event that the Company consummates an equity financing that is not a “qualified financing,” as described above, prior to the maturity of the October 2011 Notes, into the equity securities issued in the equity financing, or (ii) upon maturity of the October 2011 Notes, if the October 2011 Notes have not been previously converted, into shares of the Company’s Series C-2 convertible preferred stock.
	On July 31, 2012, upon closing of the IPO, the principal and accrued interest under the Company’s October 2011 Notes amounting to $15.6 million converted into 1,556,816 shares of common stock. The carrying value, (net of discount) and accrued interest under the Company’s October 2011 Notes was $14.9 million as of July 31, 2012.
	October 2011 Call Option Liability
	The October 2011 Purchase Agreement also provides that so long as there has not been a qualified financing, change of control or initial public offering, on or before June 30, 2012, or in the event that the October 2011 Notes issued in the initial closing or subsequent initial closings have not been previously converted into common or preferred stock as set forth in the agreement, upon the election and approval of the holders of 66% of the principal amount of the then-outstanding October 2011 Notes, the Company will issue (i) notes with an aggregate principal amount of $7.5 million or (ii) up to $7.5 million of notes in the event all or a portion of the subsequent initial closing notes have been issued. The additional note amount was determined to be a call option (“October 2011 call option”) that was recorded at its fair value of $0.8 million as a debt discount that has been amortized to interest expense over the term of the October 2011 Notes.
	The Company recorded $0.7 million to other income (expense), net in its consolidated statements of operations upon issuance of the second closing of the October 2011 Notes in February 2012 for $7.5 million. As of December 31, 2012, the April 2011 Notes and October 2011 Notes were no longer outstanding as they had converted into shares of common stock upon the closing of the Company’s IPO on July 31, 2012. During the year ended December 31, 2012, the Company recorded amortization for debt discount of $0.9 million related to the October 2011 Notes.
	In addition, the Company determined that the April 2011 Notes and the October 2011 Notes have contingent beneficial conversion features related to the conversion options described above. Upon the occurrence of the contingent event underlying those conversion options, the Company may recognize a charge based on the difference, if any, between the adjusted conversion price and the fair market value of common stock at the original issuance date. This charge, if any, will impact net income (loss) attributable to common stockholders and basic and diluted net income (loss) per share attributable to common stockholders.
	The Company determined that no beneficial conversion features exist at the dates of issuance of the April 2011 Notes and October 2011 Notes and upon closing of the IPO on July 31, 2012, at which time these notes were converted to common stock.

	April 2012 and September 2012 Notes Payable
	In April 2012, the Company borrowed $10.0 million (the “April 2012 Notes”) pursuant to a loan and security agreement (the “Original Loan Agreement”) with Silicon Valley Bank and Leader Lending, LLC—Series B (the “Lenders”). The loan carried an interest rate of 8.88%, with interest only payments for the period of 9 months from May 1, 2012. The loan is then payable in equal monthly principal payments plus interest over a period of 27 months from February 1, 2013. In connection with the Loan Agreement, the Company granted a security interest in all of its assets, except intellectual property. The Company’s obligations to the Lenders include restrictions on borrowing, asset transfers, placing liens or security interest on its assets including the Company’s intellectual property, mergers and acquisitions and distributions to stockholders. The Loan Agreement also requires the Company to provide the Lenders monthly financials and compliance certificate within 30 days of each month end, annual audited financials within 180 days of each fiscal year-end and annual approved financial projections. The Company issued warrants to the Lenders to purchase a total of 75,974 shares of common stock with an exercise price of $4.08 per share. The Loan Agreement requires immediate repayment of amounts outstanding upon an event of default, as defined in the Loan Agreement, which includes events such as a payment default, a covenant default or the occurrence of a material adverse change, as defined in the Loan Agreement. In addition, a final payment equal to 6.5% of the principal loan amount is due on the earlier of (i) maturity date, (ii) prepayment of the loan or (iii) an event of default.
	Pursuant to the terms of the Original Loan Agreement, once the Company raises at least $30.0 million from the sale of equity securities or subordinated debt, the Lenders also agreed to lend the Company a one-time single loan in the amount of $2.5 million (the “Bank Term Loan”). In September 2012, the Company borrowed an additional $2.5 million (the “September 2012 Note”) from Silicon Valley Bank pursuant to the terms of the Bank Term Loan. In addition, the Company issued warrants to Silicon Valley Bank to purchase a total of 8,408 shares of common stock with an exercise price of $5.05 per share. A final payment equal to 6.5% of the principal loan amount is due on the earlier of (i) maturity date, (ii) prepayment of the loan or (iii) an event of default. The principal amount outstanding under the Bank Term Loan accrues interest at a per annum rate equal to the greater of (i) 8.88% and (ii) the Treasury Rate, as defined in the Loan Agreement, on the date the loan is funded plus 8.50%, with interest only payments for the period of 9 months from the date the loan is funded. The loan is then payable in equal monthly principal payments plus interest over a period of 27 months from the date the loan is funded. These loans were extinguished during the year ended December 31, 2014.
	Term Loans
	On July 18, 2014, the Company entered into a new Loan and Security Agreement (the “Loan Agreement”) with Silicon Valley Bank (“SVB”), providing for two tranches of term loans of up to $16.0 million (the “Term Loans”) and a revolving credit line of up to $5.0 million (the “Revolving Loans”). In July 2014, the Company drew down both tranches of the Term Loans, of which approximately $5.8 million was used to pre-pay the Company’s existing April and September 2012 notes payable. In addition, the Company drew down $2.0 million from the revolving line of credit facility. The actual amount of the Revolving Loans that are available from time to time under the Loan Agreement is limited to a borrowing base amount that is determined according to, among other things, a percentage of the value of eligible accounts.
	In accordance with ASC Topic No. 470, “Debt – Modifications and Extinguishments” (Topic No. 470), the new loan agreement was determined to be an extinguishment of the existing debt and an issuance of new debt. As a result of the extinguishment, the Company recorded a $0.6 million loss on extinguishment of debt which includes the remaining unamortized portion of the debt discount and debt issue costs associated with the April and September 2012 loans. The loss on extinguishment of debt was included within interest expense in the Company’s consolidated statements of operations.
	The Company’s obligations under the Loan Agreement are collateralized by a first priority security interest in substantially all of the Company’s assets, excluding its intellectual property. The Company has also agreed not to pledge or otherwise encumber its intellectual property assets, except that the Company may grant licenses of its intellectual property as set forth in the Loan Agreement.
	The Company is required to pay interest only for the first 18 months of the Term Loans, followed by 30 equal monthly payments of interest and principal. The Term Loans will mature on June 30, 2018. The Revolving Loans will mature on July 18, 2017. The Loan Agreement provides for an interest rate of 4.0% per year on the Term Loans and the prime rate plus 0.75% per year on the Revolving Loans, with a minimum interest requirement on the Revolving Loans. Upon the maturity date of the Term Loans, a final payment fee of 6.75% of the original principal amount of such Term Loans (the “Final Payment”) will be due.
	The Loan Agreement contains customary representations, warranties and covenants (including the requirement to meet one of two financial covenants) by the Company, as well as customary events of default and indemnification obligations of the Company. The financial covenants include maintaining liquidity ratio on a monthly basis and achieving revenue projections on a quarterly basis as defined in the agreement. The Loan Agreement also requires the Company to provide SVB reports and compliance certificate within 30 days of each month end, quarterly financial statements within 45 days of the end of the quarter and annual audited financials within 180 days of each fiscal year-end and annual approved financial projections. The Loan Agreement requires immediate repayment of amounts outstanding upon an event of default, as defined in the Loan Agreement, which includes events such as a payment default, a covenant default or the occurrence of a material adverse change, as defined in the Loan Agreement. Upon an event of default, after any applicable grace or cure period, all amounts owed under the Loan Agreement may be declared due and payable, including the original principal amount of the Loans, the accrued but unpaid interest thereon, the Final Payment and the prepayment fee. In addition, the Loan Agreement also requires the Company to maintain its depository accounts, operating accounts, securities accounts and all foreign exchange transactions with SVB and SVB bank’s affiliates which accounts shall represent at least the lesser of (i) seventy five percent (75%) of the dollar value of the Company and its Subsidiaries’ accounts at all financial institutions or (ii) $40.0 million; provided, however, that the Company’s obligation relating to foreign exchange transactions is subject to SVB providing commercially competitive exchange rates.
	Amortization of debt discount related to the April and September 2012 notes and term loans was $0.8 million, $0.5 million and $0.4 million for the years ended December 31, 2014, 2013 and 2012, respectively.

	Future minimum payments under the Loan Agreement as of December 31, 2014 are as follows (in thousands):


	Years Ending December 31,
	2015		$	730
	2016			6,822
	2017			8,786
	2018			4,450

	Total future minimum payments		$	20,788
	Less: amount representing unamortized interest			(1,709	)
	Less: amount representing debt discount			(955	)

	Total minimum payments		$	18,124
	Less: current portion			—

	Non-current portion		$	18,124

Warrants

Warrants	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Warrants	12	Warrants
	In connection with a Loan and Security Agreement entered into in October 2007, the Company issued warrants to purchase 274 shares of Series B convertible preferred stock. In June 2009, as part of the recapitalization, these warrants were converted into warrants to purchase shares of common stock. The warrants were exercisable at $1,913.05 per share and expire in October 2017 (the “October 2007 common stock warrants”). The October 2007 common stock warrants were outstanding as of December 31, 2014 and 2013.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	13	Commitments and Contingencies
	Operating Leases
	On October 14, 2013, the Company entered into a lease agreement with 2000 Sierra Point Parkway LLC (“Landlord”) under which the Company will lease approximately 20,116 rentable square feet of office space in Brisbane, California. The initial term of the lease is six years and the lease commencement date is November 19, 2013. On December 12, 2013, the Company entered into the First Amendment to the Lease (“First Amendment”) under which the Company will lease approximately 352 rentable square feet of storage space. In addition to operating expenses and certain other additional expenses set forth in the Leases, the Company will pay total base rent of approximately $4.5 million during the initial term of the Leases.
	The Company recognizes rent expense on a straight-line basis over the lease period with monthly base rent of approximately $0.1 million. In addition, the Company also leases certain office equipment under an operating lease, which expires in December 2016.

	Aggregate total future minimum lease payments under operating facility and equipment leases as of December 31, 2014 were as follows (in thousands):


	Years Ending December 31,
	2015		$	797
	2016			820
	2017			821
	2018			845
	2019			766

	Total		$	4,049

	Rent expense including maintenance fees for the year ended December 31, 2014, 2013 and 2012 was $0.8 million, $0.4 million and $0.3 million, respectively.
	Contingencies
	In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future, but have not yet been made. Further, the Company may be subject to certain contingent liabilities that arise in the ordinary course of its business activities. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated.
	In accordance with the Company’s amended and restated certificate of incorporation and amended and restated bylaws, the Company has indemnification obligations to its officers and directors for certain events or occurrences, subject to certain limits, while they are serving at the Company’s request in such capacity. There have been no claims to date and the Company has a director and officer insurance policy that may enable it to recover a portion of any amounts paid for future claims.
	The Company is contingently committed for development milestone payments as well as sales-related milestone payments and royalties relating to potential future product sales under the restated collaboration agreement and purchase agreement with Ucyclyd (Note 3). The amount, timing and likelihood of these payments are unknown as they are dependent on the occurrence of future events that may or may not occur, including approval by the FDA of GPB for HE.
	Other Matters
	From time to time, the Company is a party to or otherwise involved in legal proceedings, claims and government inspections and other legal matters arising in the ordinary course of business or otherwise.
	On March 17, 2014, the Company received notification of a Paragraph IV certification from the generic drug manufacturer Par Pharmaceutical, Inc. (“Par”) that it had filed an Abbreviated New Drug Application with the FDA seeking approval for a generic version of RAVICTI Oral Liquid. The Paragraph IV certification alleges that certain of the Company’s patents are invalid and/or will not be infringed by Par’s manufacture, use or sale of the product for which the ANDA was submitted. The Company filed suit against Par on April 23, 2014 to protect its patents and to obtain a stay of the FDA’s approval of Par’s ANDA. On July 22, 2014, Par filed a motion to dismiss for lack of personal jurisdiction, or in the alternative, a motion to transfer the case to the Southern District of New York. The Company will oppose the motion.
	On September 22, 2014, CBI filed suit against the Company in Superior Court of the state of Delaware for New Castle County alleging breach of contract and breach of the implied covenant of good faith and fair dealing under the SPA with CBI relating related to the acquisition of Andromeda. CBI’s suit alleges $200.0 million in damages arising from the announcement on September 8, 2014 of the Company’s decision to terminate development of DiaPep277 after uncovering evidence of serious misconduct by certain Andromeda employees that compromised clinical trial results. The Company disputes CBI’s allegations. CBI has not served the complaint on the Company. On January 16, 2015, CBI dismissed its claim against the Company without prejudice. On February 16, 2015 the Company reached an agreement to settle with CBI and Yeda, the company from which Andromeda licenses the underlying DiaPep277 technology, DiaPep277 related claims against one another, and the Company granted CBI an option to acquire all of the outstanding stock of Andromeda. In connection with the agreement, CBI will transfer to the Company $2.5 million in shares of the common stock it holds, valued at the average closing price of the Company’s common stock for the fifteen trading days ending on February 11, 2015. The parties have appointed a steering committee to oversee the completion of the clinical trial with representatives of CBI and Yeda and a non-voting member appointed by the Company. The Company’s estimated budget from October 1, 2014 through the completion of the trial remains unchanged at $10.5 million. Any increase to this budget beyond $2.25 million, if incurred as a result of the direction of the steering committee, shall require CBI to reimburse those expenses in shares of the Company’s common stock. Under the agreement, CBI’s option is exercisable through September 30, 2015 for $3.5 million payable in shares of the Company’s common stock. In addition, if the option is exercised, then Andromeda will be obligated to pay Hyperion future contingent payments if and to the extent it or its shareholders receive revenues or certain other proceeds, which are capped at $36.5 million. This amount, together with the option exercise price that Hyperion may receive, approximates the total amount Hyperion will have invested in Andromeda by the option exercise date. Under the agreement, in the event that CBI does not exercise its option, the underlying DiaPep277 technology will revert to Yeda under the license agreement between Andromeda and Yeda. Also on February 16, 2015, the Company entered into a release with Evotec pursuant to which Evotec released its previously asserted claims to a milestone payment from the Company in connection with the acquisition of Andromeda and that it had suffered harm from recent incidents in relation to Diapep277in exchange for a payment of $500,000 from the Company.

Preferred_Stock

Preferred Stock	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Preferred Stock	14	Preferred Stock
	On July 31, 2012, upon the closing of the IPO, the Company’s Series C-1 and Series C-2 preferred stock amounting to $58.3 million converted into 1,912,598 and 4,663,039 shares of common stock, respectively. On July 31, 2012, the Company amended its Certificate of Incorporation to decrease the number of authorized shares of preferred stock to 10,000,000 with a par value of $0.0001 per share. Pursuant to the Company’s amended and restated certificate of incorporation, the board of directors has the authority, without action by its stockholders, to designate and issue shares of preferred stock in one or more series and to fix the rights, preferences, privileges and restrictions thereof.
	As of December 31, 2014 and 2013, there was no preferred stock outstanding.

Common_Stock

Common Stock	12 Months Ended
Common Stock	Dec. 31, 2014
Text Block [Abstract]
Common Stock	15	Common Stock
	On July 31, 2012, the Company completed its IPO and issued 5,000,000 shares of its common stock at an initial offering price of $10.00 per share. In addition, the Company sold an additional 750,000 shares of common stock directly to its underwriters when they exercised their over-allotment option in full at the initial offering price of $10.00 per share. The shares began trading on the NASDAQ Global Market on July 26, 2012. The Company received net proceeds from the IPO of $51.3 million, after deducting underwriting discounts and commissions of $4.0 million and expenses of $2.2 million.
	On July 31, 2012, upon the closing of the IPO, the Company’s Series C-1 and Series C-2 preferred stock amounting to $58.3 million converted into 1,912,598 and 4,663,039 shares of common stock, respectively. In addition, the principal and accrued interest under the Company’s April 2011 Notes and October 2011 Notes amounting to $18.9 million and $15.6 million, respectively, converted into 1,888,054 and 1,556,816 shares of common stock. As of July 31, 2012, the carrying values and accrued interest under the April 2011 Notes and October 2011 Notes amounted to $18.4 million and $14.9 million, respectively. Additionally, the April 2011 common stock warrants and October 2011 preferred stock warrants were converted into 322,599 and 17,762 shares of common stock, respectively, immediately prior to the closing of the IPO. The fair value of the April 2011 common stock warrants and October 2011 preferred stock warrants as of July 31, 2012 of $3.9 million was reclassified to additional paid-in capital.
	In addition, on July 31, 2012, the Company amended its Certificate of Incorporation to increase the number of authorized shares of common stock to 100,000,000 with a par value of $0.0001 per share.
	Common stockholders are entitled to dividends when and if declared by the Board of Directors subject to prior rights of the preferred stockholders. The holder of each share of common stock is entitled to one vote.
	On March 13, 2013, the Company completed a follow-on offering and issued 2,875,000 shares of its common stock at an offering price of $20.75 per share. In addition, the Company sold an additional 431,250 shares of common stock directly to its underwriters when they exercised their over-allotment option in full at an offering price of $20.75 per share. The Company received net proceeds from the offering of $63.7 million, after deducting underwriting discounts and commissions of $4.1 million and expenses of $0.8 million.
	On August 14, 2013, the Company filed a shelf registration statement on Form S-3, which was declared effective by the SEC on September 13, 2013. The shelf registration statement permits: (a) the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $150.0 million of its common stock, preferred stock, debt securities, warrants and/or units; (b) the sale of up to 8,727,000 shares of common stock by certain selling stockholders; and (c) the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $50.0 million of its common stock that may be issued and sold under a sales agreement with Cantor Fitzgerald & Co. As of December 31, 2014, there were no sales of any securities registered pursuant to the shelf registration statement.
	At December 31, 2014, the Company had reserved common stock for future issuances as follows:


	Issuance of options under 2012 stock plan		688,842
	Issuance upon exercise of options under the 2006 and 2012 stock plan		3,068,741
	Issuance upon vesting of restricted and performance stock units under the 2012 stock plan		136,293
	Issuance upon exercise of October 2007 common stock warrants		274

	Total		3,894,150

Stock_Option_Plan

Stock Option Plan	12 Months Ended
Stock Option Plan	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option Plan	16	Stock Option Plan
	2006 Plan
	In December 2006, the Company adopted the 2006 Equity Incentive Plan (the “2006 Plan”), under which 457 shares of the Company’s common stock had been originally reserved for issuance to employees, directors and consultants. The 2006 Plan provides for the grant of the following stock awards: incentive stock options, non-statutory stock options, restricted stock awards, restricted stock unit awards and stock appreciation rights. Incentive stock options may be granted only to Company employees, which include officers and directors of the Company. Non-statutory stock options and stock purchase rights may be granted to employees and consultants. Stock awards other than incentive stock options may be granted to employees, directors and consultants.
	The Board of Directors has the authority to determine to whom options will be granted, the number of options, the term and the exercise price. The exercise price of the stock option shall not be less than 100% of the fair market value of the common stock subject to the option on the date the option is granted. For individuals holding more than 10% of the voting rights of all classes of stock, the exercise price of an option will not be less than 110% of fair market value and the option is not exercisable after the expiration of five years from the date of the grant. Options granted to an employee who is not an officer, director or consultant shall provide for vesting of the total number of shares of common stock at a rate of at least 20% per year over five years from the date the option was granted, subject to reasonable conditions such as continued employment, at any time or during any period established by the Company. The contractual term of each option is ten years.
	On July 25, 2012, the effective date of the 2012 Plan, the 2006 Plan was frozen and no additional awards will be made under the 2006 Plan. Any shares remaining available for future grant were allocated to the 2012 Plan and any shares underlying outstanding options that terminate by expiration, forfeiture, cancellation, or otherwise without issuance of such shares, will be allocated to the 2012 Plan.
	Activity under the 2006 Plan is as follows:


							Outstanding Options
			Number of Shares				Number of Shares				Weighted-Average
			Available for				Underlying				Exercise Price Per
			Grant				Outstanding				Share
							Options
	Balances at December 31, 2013			—				1,538,197				3.64
	Options exercised			—				(190,263	)			3.73
	Options cancelled			14,413				(14,413	)			6.78
	Options re-allocated to 2012 Plan			(14,413	)			—				—

	Balances at December 31, 2014			—				1,333,521			$	3.6

	The aggregate intrinsic value of options exercised for the year ended December 31, 2014 was $4.1 million. Intrinsic value is calculated as the difference between the exercise price of the underlying options and the fair value of the common stock for the options that had exercise prices that were lower than the fair value per share of the common stock on the date of exercise.

	Aggregate options outstanding and vested and exercisable by exercise price at December 31, 2014 for the 2006 plan are as follows (dollars in thousands except per share values):


	Options Outstanding													Options Vested and Exercisable
	Exercise		Number				Aggregate				Weighted			Number				Aggregate			Exercise
	Price		Outstanding				Intrinsic				Average			Outstanding				Intrinsic			Price
							Value				Remaining							Value
											Life (in Years)
	$ 1.28			735,773			$	16,717				4.5			735,773			$	16,717		$	1.28
	$ 4.08			252,403				5,028				6.3			228,490				4,552		$	4.08
	$ 7.31			344,405				5,748				7.3			217,060				3,623		$	7.31
	$ 327.95			940				—				2.5			940				—		$	327.95

				1,333,521			$	27,493				5.5			1,182,263			$	24,892

	The intrinsic values of outstanding, vested and exercisable options were determined by multiplying the number of shares by the difference in exercise price of the options and the fair value of the common stock as of December 31, 2014 of $24.00 per share.
	For the year ended December 31, 2014, options vested and expected to vest for the 2006 plan aggregated to 1,328,822 options with an intrinsic value of $27.4 million, weighted average exercise price of $3.59 per share and the weighted average remaining life of 5.5 years.
	2012 Plan
	In April 2012, the board of directors of the Company adopted (approved by Company’s stockholders in July 2012) the 2012 Omnibus Incentive Plan (the “2012 Plan”). The 2012 Plan provides for the grant of stock options, stock appreciation rights, restricted stock, unrestricted stock, stock units, dividend equivalent rights, other equity-based awards and cash bonus awards. The 2012 Plan became effective on July 25, 2012.
	As of December 31, 2014 and 2013, the Company had reserved 688,842 shares and 576,760 shares of common stock, respectively, for issuance under the 2012 Plan.

	Activity under the 2012 Plan is as follows:


							Outstanding Options							Restricted Stock Units							Performance Stock Units
							Outstanding Options							Outstanding							Outstanding
			Number of Shares				Number of Shares				Weighted-Average			Number of Shares				Grant			Number of Shares		Grant
			Available for				Underlying				Exercise Price Per			Underlying				Date			Underlying		Date
			Grant				Outstanding				Share			Outstanding				Fair Value			Outstanding		Fair Value
							Options							RSU’s							RSU’s
	Balances at December 31, 2013			576,760				1,252,433				20.75			18,000				19.39			—		—
	Additional shares authorized			805,485				—				—			—				—			—		—
	Options and awards granted			(938,062	)			806,919				25.99			122,155				26.68			8,988		25.08
	Options exercised			—				(101,736	)			18.42			—				—			—		—
	Awards released			—				—				—			(5,000	)			20.13			—		—
	Options re-allocated to 2012 Plan			14,413				—				—			—				—			—		—
	Options and awards cancelled			230,246				(222,396	)			22.66			(7,850	)			26.74			—		—

	Balance at December 31, 2014			688,842				1,735,220			$	23.08			127,305			$	25.9			8,988	$	25.08

	The aggregate intrinsic value of options exercised for the year ended December 31, 2014 was $0.8 million.
	Aggregate options outstanding and vested and exercisable by exercise price at December 31, 2014 for the 2012 plan are as follows (dollars in thousands except per share values):


		Options Outstanding											Options Vested and Exercisable
Exercise Price		Number				Aggregate				Weighted			Number				Aggregate			Exercise
		Outstanding				Intrinsic				Average			Outstanding				Intrinsic			Price
						Value				Remaining							Value
										Life (in Years)
$10.32- 18.24			242,962			$	2,799				7.9			118,837			$	1,415		$	10.32 - 18.24
$19.39- 21.05			200,170				746				9			36,504				162			19.39 - 21.05
$21.45- 24.38			128,450				220				8.7			41,514				83			21.45 - 24.38
$24.46- 26.74			1,095,725				—				8.8			253,207				—			24.46 - 26.74
$26.97- 28.08			42,313				—				9.3			—				—			26.97 - 28.08
$29.27- 31.00			25,600				—				9.3			—				—			29.27 - 31.00

			1,735,220			$	3,765				8.7			450,062			$	1,660

The intrinsic values of options vested and exercisable options as of December 31, 2014 were determined by multiplying the number of shares by the difference in exercise price of the options and the fair value of the common stock as of December 31, 2014 of $24.00 per share.
For the year ended December 31, 2014, options vested and expected to vest for the 2012 plan aggregated to 1,646,570 options with an aggregate intrinsic value of $3.6 million, weighted average exercise price of $23.02 per share and the weighted average remaining life of 8.7 years.

Stock-Based Compensation
During the years ended December 31, 2014, 2013 and 2012 , the Company granted stock options to employees to purchase 806,919, 1,067,315 and 720,580 shares of common stock, respectively, with a weighted-average grant date fair value of $25.99, $22.90 and $6.76 per share, respectively. During the year ended December 31, 2014 and 2013, the Company granted 122,155 and 21,000 restricted stock units, respectively, to employees. There were no restricted stock units granted for the year ended December 31, 2012. During the year ended December 31, 2014, the Company granted 8,998 performance stock units to employees. There were no performance stock units granted for the years ended December 31, 2013 and 2012.
Stock-based compensation expense recognized during the years ended December 31, 2014, 2013 and 2012 includes compensation expense for stock-based awards granted to employees based on the grant date fair value estimated in accordance with the provisions of ASC 718 of $7.6 million, $4.3 million and $1.0 million, respectively. As of December 31, 2014, there was a total unrecognized compensation cost of $17.0 million related to unvested stock-based awards granted. These amounts are expected to be recognized over a period of approximately 2.5 years.
The Company determines the fair value of restricted stock units and performance stock units using the closing price of the Company’s common stock on the date of grant. The Company estimates the fair value of stock options using the Black-Scholes option valuation model. The fair value of employee stock options and restricted stock units are being amortized on a straight-line basis over the requisite service period of the awards. The fair value of the performance stock awards is being amortized based on the achievement of performance goals and over the requisite service period of the awards. The fair value of the employee stock options was estimated using the following weighted-average assumptions:


		Year Ended December 31,
		2014				2013				2012
Expected volatility			62.76	%			58	%			65	%
Risk-free interest rate			1.9	%			1.14	%			1.05	%
Dividend yield			0	%			0	%			0	%
Expected term (in years)			6				5.96				6
Determining Fair Value of Stock Options
The fair value of each grant of stock options was determined by the Company using the methods and assumptions discussed below. Each of these inputs is subjective and generally requires significant judgment to determine.
Expected Term — The expected term of stock options represents the weighted average period the stock options are expected to be outstanding. For option grants that are considered to be “plain vanilla”, the Company has opted to use the simplified method for estimating the expected term as provided by the Securities and Exchange Commission. The simplified method calculates the expected term as the average time-to-vesting and the contractual life of the options. For other option grants, the expected term is derived from the Company’s historical data on employee exercises and post-vesting employment termination behavior taking into account the contractual life of the award.
Expected Volatility — The expected stock price volatility assumption was determined by examining the historical volatilities of a group of industry peers and the Company’s own historical volatility since the Company began trading subsequent to its IPO in July 2012.

Risk-Free Interest Rate — The risk free rate assumption is based on U.S. Treasury instruments for which the terms were consistent with the expected term of the Company’s stock options.
Expected Dividend — The expected dividend assumption is based on the Company’s history and expectation of dividend payouts.
Forfeiture Rate — ASC 718 requires forfeitures to be estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Forfeitures were estimated based on historical experience.
Fair Value of Common Stock — Prior to the IPO, the fair value of the shares of common stock underlying the stock options has historically been the responsibility of and determined by the Company’s board of directors. Because there was no public market for the Company’s common stock, the board of directors determined fair value of common stock at the time of grant of the option by considering a number of objective and subjective factors including independent third-party valuations of the Company’s common stock, sales of convertible preferred stock to unrelated third parties, operating and financial performance, the lack of liquidity of capital stock and general and industry specific economic outlook, amongst other factors. Subsequent to the IPO, the fair value of the shares of the common stock underlying the stock options is the closing price on the option grant date.
Total stock-based compensation expense related to options and awards granted was allocated as follows (in thousands):


		Year Ended December 31,
		2014				2013				2012
Cost of sales		$	70			$	27			$	—
Research and development			1,384				585				374
Selling general and administrative			6,184				3,709				619

Total		$	7,638			$	4,321			$	993

For the years ended December 31, 2014 and 2013, stock-based compensation of $0.1 million each was capitalized into inventories. Capitalized stock-based compensation is recognized as cost of sales when the related product is sold. Allocations to research and development, general and administrative and selling and marketing expense are based upon the department to which the associated employee reported.

Income_Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	17	Income Taxes
	For the year ended December 31, 2014, the Company generated a pretax income of $30.0 million in the U.S. and a pretax loss of $36.0 million outside the U.S., for a net consolidated pretax loss of $6.0 million. For the years ended December 31, 2013 and 2012, the Company generated a pretax income of $16.7 million and a pretax loss of $32.3 million, respectively, in the U.S. In years prior to 2014, the Company has not generated any pretax income or loss outside the U.S.

	The components of the income tax expense are as follows (in thousands):


			Years ended
			December 31,
			2014				2013				2012
	Current income tax expense:
	Federal		$	736			$	—			$	—
	State			703				326				—

				1,439				326				—

	Deferred income tax benefit:
	State			(1,136	)			(277	)			—

				(1,136	)			(277	)			—

	Total income tax expense		$	303			$	49			$	—

	The reconciliation of income tax expense computed at the statutory federal income tax rate of 35% to amounts included in the consolidated statements of operations is as follows:


			Year Ended December 31,
			2014				2013				2012
	Statutory rate			35	%			35	%			34	%
	State tax			0.6	%			5.5	%			5.4	%
	Tax credits			57.5	%			(5.0	)%			0.7	%
	Stock options			(28.0	)%			0.2	%			(0.7	)%
	Valuation allowance			(81.8	)%			(29.6	)%			(37.1	)%
	Impact of Andromeda acquisition			12.6	%			—				—
	Change in federal tax rate			—				(6.0	)%			—
	Other			(1.0	)%			0.2	%			(2.3	)%

				(5.1	)%			0.3	%			0	%

	Deferred income tax assets and liabilities reflect the net tax effects of net operating loss and tax credit carryovers and the temporary differences between the carrying amounts of assets and liabilities for financial reporting and the amounts used for income tax purposes. Significant components of the Company’s deferred income tax assets are as follows (in thousands):


			Year Ended December 31,
			2014				2013
	Deferred income tax assets
	Fixed assets, capitalized intangibles and other assets		$	6,030			$	5,294
	Net operating loss			35,164				31,842
	Tax credits			23,024				18,480
	Stock-based compensation expense			1,660				1,133
	Accrued expenses and reserves			3,405				1,502
	Capitalized research and development expenses			3,237				—
	Tax basis in investments			12,624				—
	Other			381				25

	Total			85,525				58,276
	Valuation allowance			(84,113	)			(58,000	)

	Net deferred income tax assets		$	1,412			$	276

	At December 31, 2014, the non-current deferred income tax asset of $1.4 million is included in “Other non-current assets” in the consolidated balance sheets.
	At December 31, 2013, current deferred income tax asset of $0.1 million is included in “Prepaid expenses and other current assets” and the non-current deferred income tax asset of $0.2 million is included in “Other non-current assets” in the consolidated balance sheets.
	The amounts recorded as deferred income tax assets as of December 31, 2014 and 2013 represent the amount of tax benefits of existing deductible temporary differences and carryforwards that are more likely than not to be realized through the generation of sufficient future taxable income within the carryforward period. For the year ended December 31, 2014, the valuation allowance on deferred income tax asset increased by $26.1 million. The amount of net operating losses associated with excess tax deductions from stock-based compensation arrangements that is allocated to contributed capital if the future tax benefits are subsequently recognized is $4.0 million.
	At December 31, 2014, the Company had net operating loss carryforwards of approximately $36.4 million and $107.8 million available to reduce future taxable income, if any, for both federal and California state income tax purposes, respectively. In addition, the Company had $67.3 million of Israeli net operating loss carryforwards which do not expire. The net operating loss carryforwards will begin to expire in 2031 and 2028 for federal and state income tax purposes, respectively. If the Company experiences an “ownership change” for purposes of Section 382 of the Internal Revenue Code of 1986, as amended, it may be subject to annual limits on its ability to utilize net operating loss carryforwards and credits. An ownership change is, as a general matter, triggered by sales or acquisitions of its stock in excess of 50% on a cumulative basis during a three-year period by persons owning 5% or more of our total equity value. The Company determined that an ownership change occurred in 2014 resulting in an annual limitation of approximately $50 million per year. The Company also had federal and state tax credit carryforwards of approximately $22.6 million and $0.7 million respectively, at December 31, 2014. The federal credits will expire starting in 2027, if not utilized. The California credits have no expiration date.

	The Company was granted orphan drug designation in 2009 by the FDA for its products currently under development. The orphan drug designation allows the Company to claim increased federal tax credits for its research and development activities. Included in the $22.6 million of federal credit carryforwards is $21.1 million of Orphan Drug Credit claims for 2009 through 2014.
A reconciliation of the beginning and ending balances of the unrecognized income tax benefits during the years ended December 31, 2014, 2013 and 2012 is as follows (in thousands):


		Year Ended December 31,
		2014				2013				2012
Balance at the beginning of the year		$	6,269			$	5,723			$	5,357
Changes based on prior period tax positions			(2,325	)			—				(228	)
Changes based on current period tax positions			223				546				594

Balance at the end of the year		$	4,167			$	6,269			$	5,723

The entire amount of the unrecognized income tax benefits would not impact the Company’s effective tax rate if recognized.
There was no interest or penalties accrued through December 31, 2014. The Company’s policy is to recognize any related interest or penalties in income tax expense. The material jurisdictions in which the Company is subject to potential examination by tax authorities for tax years ended 2006 through the current period include the U.S. and California. The Company is not currently under income tax examinations by any tax authorities in federal, state or other jurisdictions.

Defined_Contribution_Plan

Defined Contribution Plan	12 Months Ended
	Dec. 31, 2014
Postemployment Benefits [Abstract]
Defined Contribution Plan	18	Defined Contribution Plan
	The Company sponsors a defined contribution plan under Section 401(k) of the Internal Revenue Code (“Plan”) covering substantially all full-time U.S. employees. Employee contributions are voluntary and are determined on an individual basis subject to the maximum allowable under federal tax regulations. Participants are always fully vested in their contributions. For the year ended December 31, 2014 and 2013, the Company made a contribution of $0.3 million and $0.2 million to the Plan. For the year ended December 31, 2012, the Company did not make any contributions to the Plan.

Net_Income_Loss_per_Share_of_C

Net Income (Loss) per Share of Common Stock	12 Months Ended
Net Income (Loss) per Share of Common Stock	Dec. 31, 2014
Earnings Per Share [Abstract]
Net Income (Loss) per Share of Common Stock	19. Net Income (Loss) per Share of Common Stock
	The following table sets forth the computation of basic and diluted net income (loss) per share of common stock for the periods indicated (in thousands, except share and per share amounts):


		Year Ended December 31,
		2014			2013		2012
	Net income (loss) per share
	Numerator:
	Net income (loss) attributable to common stockholders	$	(6,255	)	$	16,627	$	(32,263	)

	Denominator:
	Weighted-average number of common shares outstanding — basic		20,470,025			19,415,822		7,256,537
	Dilutive effect of stock-options and awards		—			1,315,091		—

	Weighted average common shares outstanding — dilutive		20,470,025			20,730,913		7,256,537

	Net income (loss) per share:
	Basic	$	(0.31	)	$	0.86	$	(4.45	)

	Diluted	$	(0.31	)	$	0.8	$	(4.45	)

	The following outstanding potentially dilutive securities were excluded from the computation of diluted net income (loss) per share, as the effect of including them would have been antidilutive:


		Year Ended December 31,
		2014			2013		2012
	Stock options		3,068,741			1,027,605		1,928,754
	Common stock warrants		274			274		84,656

	Total		3,069,015			1,027,879		2,013,410

Related_Party_Transaction

Related Party Transaction	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transaction	20	Related Party Transaction
	As part of the Company’s acquisition of BUPHENYL (see Note 4), the Company assumed the existing BUPHENYL distributors agreements, including the distribution agreement with Swedish Orphan Biovitrum AB (“SOBI”). Additionally, in the third quarter of 2013, SOBI was granted exclusive rights by the Company to distribute RAVICTI on a named patient basis for the chronic treatment of UCD in the Middle East. SOBI’s chairman, Bo Jesper Hansen, is a member of the Company’s Board of Directors. During the years ended December 31, 2014 and 2013, the Company recognized $5.1 million and $2.2 million, respectively, from sales to SOBI. As of December 31, 2014 and 2013, the accounts receivable from SOBI amounted to $1.5 million and $0.7 million, respectively.

Segment_Reporting

Segment Reporting	12 Months Ended
Segment Reporting	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Reporting	21	Segment Reporting
	The Company operates as one operating segment and uses one measurement of profitability to manage its business.

	Net product revenue for RAVICTI and BUPHENYL for the years ended December 31, 2014 and 2013 are as follows (in thousands):


			Year Ended
			December 31,
			2014			2013
	RAVICTI		$	95,400		$	31,236
	BUPHENYL			18,584			11,468
	Co-payment assistance			(400	)		(500	)

	Total		$	113,584		$	42,204

	Net product revenue for RAVICTI and BUPHENYL by geographic region are as follows (in thousands):


			Year Ended
			December 31,
			2014			2013
	United States		$	103,303		$	37,102
	Canada			3,723			2,208
	Rest of the world			6,558			2,894

	Total		$	113,584		$	42,204

	Long lived assets consist of property and equipment which at December 31, 2014 and 2013 are primarily in the U.S.

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events	22	Subsequent Events
	On February 16, 2015, the Company announced that it has amicably settled its disputes, and entered into a Completion of Phase 3 Clinical Trial, Option and Mutual Release Agreement (the “Release Agreement”) by and among the Company, Hyperion Therapeutics Israel Holding Corp Ltd (“Hyperion Israel”), CBI, Yeda and Andromeda regarding DiaPep277, a product candidate developed by Andromeda.
	The parties to the Release Agreement appointed a steering committee with representatives of CBI and Yeda and a non-voting member from the Company to oversee completion of the Clinical Trial, the analysis of its results, and interactions with regulatory authorities. In addition, under the Release Agreement, CBI has an option to acquire Andromeda, which option expires September 30, 2015. In consideration for the option, CBI will pay to Hyperion Israel an option payment of $2.5 million in shares of the Company’s common stock held by CBI. The shares are valued based on the average closing price of the Company’s common stock for the fifteen trading days ending on February 11, 2015. If CBI exercises its option to acquire Andromeda, the option purchase price will be $3.5 million payable in shares of the Company’s common stock currently held by CBI to Hyperion Israel. In addition, if CBI exercises its option to acquire Andromeda, Andromeda will be obligated to pay Hyperion Israel future contingent payments if and to the extent it receive revenues or its shareholders receive certain other proceeds it is acquired, liquidated or makes other distributions of assets. The aggregate amount of all future contingent payments by Andromeda to Hyperion Israel is capped at $36.5 million which, together with the option exercise price that Hyperion Israel may receive, approximates the total amount the Company will have invested in Andromeda by the option exercise date. Under the Release Agreement, the Company’s estimated budget from October 2014 through completion of the Clinical Trial shall remain unchanged at $10.5 million. Any increase to the budget beyond $2.25 million, if incurred as a result of the direction of the steering committee, shall require CBI to reimburse expenses to Hyperion Israel. In the event that CBI does not exercise the option, the DiaPep277 intellectual property will revert to Yeda under the license agreement between Andromeda and Yeda.
	Andromeda has also entered into a release agreement with Evotec International GmbH (“Evotec”) pursuant to which Andromeda has settled its disputes with Evotec regarding Evotec’s assertions that the Company’s acquisition of Andromeda triggered a €3.38 million milestone payment to it and that it suffered harm from recent incidents in relation to DiaPep277. Under the terms of the release, Evotec is releasing its claims against Andromeda in exchange for a $500,000 payment from the Company, and the Company confirms that based on its investigation of the Employee Conduct, as defined in the Release Agreement, it believes that neither Evotec nor its legal predecessor (i) had any involvement in any aspect or decision-making regarding the development of DiaPep277 and likewise, (ii) DeveloGen AG was also not involved in any way in the further development of DiaPep277 after selling it to Andromeda in June 2007, and had no role in the data generation and analyses. For the year ended December 31, 2014, the Company had $4.6 million included in “Accrued liabilities” in the Consolidated Balance Sheets. The Company considers this as a (Type 2) Subsequent event and will recognize $4.1 million as “Other Income” in the Consolidated Statements of Operations in the Quarterly Report on Form 10-Q for the period ended March 31, 2015.

Selected_Quarterly_Financial_D

Selected Quarterly Financial Data	12 Months Ended
Selected Quarterly Financial Data	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data	23	Selected Quarterly Financial Data (Unaudited)
	The following table presents selected unaudited quarterly financial information for the years ended December 31, 2014, 2013 and 2012. 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 Quarters Ended
	(in thousands, except share and per share amounts)		December 31,		September 30,⁽¹⁾			June 30,		March 31,
	Year Ended December 31, 2014
	Product revenue, net		$	30,805	$	26,201		$	37,095	$	19,483
	Costs and expenses		$	24,078	$	55,031		$	20,898	$	17,784
	Net income (loss) attributable to common stockholders		$	7,096	$	(32,793	)	$	18,183	$	1,259
	Net income (loss) per share attributable to common stockholders — basic		$	0.34	$	(1.59	)	$	0.89	$	0.06
	Net income (loss) per share attributable to common stockholders — diluted		$	0.32	$	(1.59	)	$	0.84	$	0.06

			For The Quarters Ended
	(in thousands, except share and per share amounts)		December 31,		September 30,			June 30,⁽²⁾		March 31,
	Year Ended December 31, 2013
	Product revenue, net		$	18,627	$	15,489		$	7,305	$	783
	Costs and expenses		$	17,747	$	15,037		$	12,986	$	9,851
	Net income (loss) attributable to common stockholders		$	468	$	112		$	25,022	$	(8,975	)
	Net income (loss) per share attributable to common stockholders — basic		$	0.02	$	0.01		$	1.25	$	(0.52	)
	Net income (loss) per share attributable to common stockholders — diluted		$	0.02	$	0.01		$	1.17	$	(0.52	)

	-1	For the quarter ended September 30, 2014, the Company recorded $30.2 million as an impairment charge of goodwill on the Company’s consolidated statements of operations. Also refer to the information contained in Note 4 of the consolidated financial statements appearing elsewhere in the report.

	-2	For the quarter ended June 30, 2013, the Company recorded a gain of $31.1 million related to the BUPHENYL acquisition on the consolidated statements of operations. Also refer to the information contained in Note 4 of the consolidated financial statements appearing elsewhere in the report.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation and the Use of Estimates	Basis of Presentation and the Use of Estimates
	The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The preparation of the accompanying consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, the Company evaluates its estimates, including those related to the fair value of assets and liabilities, intangible asset valuation, acquisition-related contingent consideration, acquisition related contingent liability, impairment of goodwill and intangible assets, stock-based compensation expense, income taxes, revenue recognition and product sales allowances. Management bases its estimates on historical experience or on various other assumptions, including information received from its service providers, which it believes to be reasonable under the circumstances. Actual results could differ from those estimates.
Basis of Consolidation	Basis of Consolidation
	The consolidated financial statements include the Company’s accounts and those of its wholly-owned subsidiaries: Hyperion Therapeutics Ltd., Hyperion Therapeutics Ireland Holding Ltd., Hyperion Therapeutics Ireland Operating Ltd., Hyperion Therapeutics Israel Holding Corp. Ltd., Penville Limited and Andromeda Biotech Ltd. All intercompany accounts and transactions have been eliminated.
Concentration of Credit Risk and Significant Customers	Concentration of Credit Risk and Significant Customers
	The Company’s cash and cash equivalents and investments are maintained with financial institutions located in and outside the United States. Deposits in these institutions may exceed the amount of insurance provided on such deposits. The Company has not recognized any losses from credit risks during the periods presented and management does not believe that the Company is exposed to significant credit risk from its cash and cash equivalents or investments.
	The Company is also subject to credit risk from its accounts receivables related to its product sales. The Company monitors its exposure within accounts receivable and records a reserve against uncollectible accounts receivable as necessary. The Company extends credit to a specialty distributor in the United States and to international distributors, pharmacies and hospitals outside the United States. Customer creditworthiness is monitored and collateral is not required. As of December 31, 2014, there were no credit losses on the Company’s accounts receivable. As of December 31, 2014 and 2013, the specialty distributor in the United States accounted for 87% and 64% of accounts receivable balance, respectively. One international distributor accounted for 10% and 17% of the accounts receivable balance for the year ended December 31, 2014 and 2013, respectively.
	The specialty distributor accounted for 91% and 88% of the net product revenue for the year ended December 31, 2014 and 2013, respectively.
Fair Value of Financial Instruments	Fair Value of Financial Instruments
	The Company measures certain financial assets and liabilities at fair value based on the exchange price that would be received for an asset or paid for 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 carrying amounts of the Company’s financial instruments, including cash equivalents, short-term investments, accounts payable, and accrued liabilities, approximate fair value due to their short maturities. The carrying amounts of long-term investments, acquisition-related contingent consideration and acquisition related contingent liability represent their estimated fair values. The fair value of the notes payable are based on the present value of expected future cash flows and assumptions about current interest rates and the creditworthiness of the Company.
Business Combinations	Business Combinations
	The Company allocates the purchase price of an acquired business to the tangible and intangible assets acquired and liabilities assumed based upon their
Cash and Cash Equivalents	Cash and Cash Equivalents
	The Company considers all highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. Cash and cash equivalents include money market funds and various deposit accounts.
Investments	Investments
	The Company determines the appropriate classification of its investments in debt and equity securities at the time of purchase. All of the Company’s securities are classified as available-for-sale and reported in short-term investments or long-term investments based on maturity dates and whether such assets are reasonably expected to be realized in cash or sold or consumed during the normal cycle of business. Available-for-sale investments are recorded at fair value, with unrealized gains or losses included in Accumulated Other Comprehensive Loss on the Company’s Consolidated Balance Sheets, exclusive of other-than-temporary impairment losses, if any. Short-term and long-term investments are comprised of corporate notes, commercial paper, U.S. federal government agency securities and certificates of deposit.
Accounts Receivable	Accounts Receivable
	Trade accounts receivable are recorded net of product sales allowances for prompt-payment discounts, chargebacks, and doubtful accounts. Estimates for chargebacks and prompt-payment discounts are based on contractual terms, historical trends and expectations regarding the utilization rates for these programs. At December 31, 2014, the Company had no allowances for doubtful accounts.
Inventories	Inventories
	Inventories are valued at the lower of cost or market, with cost computed at standard cost (which approximates actual cost) on a first-in-first-out (FIFO) cost method and consists of raw materials, work-in-progress and finished goods. Costs capitalized as inventories include third party manufacturing costs, associated compensation related costs of personnel indirectly involved in the manufacturing process and other overhead costs such as ancillary supplies. Subsequent to FDA approval of RAVICTI on February 1, 2013, the Company began capitalizing RAVICTI inventories as the related costs were expected to be recoverable through the commercialization of the product. Costs incurred prior to the FDA approval of RAVICTI have been recorded as research and development expense in the consolidated statements of operations. If information becomes available that suggest that inventories may not be realizable, the Company may be required to expense a portion or all of the previously capitalized inventories.
	Products that have been approved by the FDA or other regulatory authorities, such as RAVICTI, are also used in clinical programs, to assess the safety and efficacy of the products for usage in diseases that have not been approved by the FDA or other regulatory authorities. The form of RAVICTI utilized for both commercial and clinical programs is identical and, as a result, the inventory has an “alternative future use” as defined in authoritative guidance. Raw materials and purchased drug product associated with clinical development programs are included in inventory and charged to research and development expense when the product enters the research and development process and no longer can be used for commercial purposes and, therefore, does not have an “alternative future use”.
Intangible Assets	Intangible Assets
	Intangible assets are recorded at acquisition cost less accumulated amortization and impairment. Intangible asset with finite lives are amortized over their estimated useful life using the economic use method, which reflects the pattern that the economic benefits of the intangible asset are consumed as revenue is generated. The pattern of consumption of the economic benefits is estimated using the future projected cash flows of the intangible asset.
IPR&D	IPR&D
	The fair value of IPR&D acquired through a business combination is capitalized as an indefinite-lived intangible asset until the completion or abandonment of the related research and development activities. When the related research and development is completed, the asset is assigned a useful life and amortized.

	The fair value of an IPR&D intangible asset is determined using an income approach. This approach starts with a forecast of the net cash flows expected to be generated by the asset over its estimated useful life. The net cash flows reflect the asset’s stage of completion, the probability of technical success, the projected costs to complete, expected market competition, and an assessment of the asset’s life-cycle. The net cash flows are then adjusted to present value by applying an appropriate discount rate that reflects the risk factors associated with the cash flow streams.
Goodwill	Goodwill
	Goodwill represents the excess of the purchase price of acquired businesses over the estimated fair value of the identifiable net assets acquired. Goodwill is not amortized but is tested for impairment at least annually at the reporting unit level or more frequently if events or changes in circumstances indicate that the asset might be impaired.
	Goodwill is tested for impairment annually or more frequently if events or changes in circumstances between annual tests indicate that the asset may be impaired. Impairment loss is recognized based on a comparison of the fair value of the asset to its carrying value, without consideration of any recoverability.
Impairment of Long-lived Assets	Impairment of Long-lived Assets
	The Company reviews its property and equipment, intangible assets subject to amortization and other long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset class may not be recoverable. Indicators of potential impairment include: an adverse change in legal factors or in the business climate that could affect the value of the asset; an adverse change in the extent or manner in which the asset is used or is expected to be used, or in its physical condition; and current or forecasted operating or cash flow losses that demonstrate continuing losses associated with the use of the asset. If indicators of impairment are present, the asset is tested for recoverability by comparing the carrying value of the asset to the related estimated undiscounted future cash flows expected to be derived from the asset. If the expected cash flows are less than the carrying value of the asset, then the asset is considered to be impaired and its carrying value is written down to fair value, based on the related estimated discounted future cash flows.
	Indefinite-lived intangible assets, including acquired IPR&D, are tested for impairment annually or more frequently if events or changes in circumstances between annual tests indicate that the asset may be impaired. Impairment losses on indefinite-lived intangible assets are recognized based on a comparison of the fair value of the asset to its carrying value, without consideration of any recoverability.
Acquisition-Related Contingent Consideration	Acquisition-Related Contingent Consideration
	Acquisition-related contingent consideration, which consists primarily of potential milestone payments and royalty obligations, is recorded in the consolidated balance sheets at its acquisition date estimated fair value, in accordance with the acquisition method of accounting. The fair value of the acquisition-related contingent consideration is remeasured each reporting period, with changes in fair value recorded in the consolidated statements of operations. Changes in the fair value of the acquisition-related contingent consideration obligations result from several factors including changes in discount periods and rates, changes in the timing and amount of revenue estimates and changes in probability assumptions with respect to the likelihood of achieving specified milestone criteria. The fair value measurement is based on significant inputs not observable in the market and thus represents a Level 3 measurement as defined in the fair value hierarchy.
Acquisition-Related Contingent Liability	Acquisition-Related Contingent Liability
	Acquisition-related contingent liability, which consists primarily of potential milestone payments and royalty obligations, and potential payments to certain employees of Andromeda is recorded in the consolidated balance sheets at its acquisition date estimated fair value. The Company reassesses the probability and estimates associated with the contingent liability at each reporting period. For liability payable to third parties, any increase in the liability is recorded in the consolidated statements of operations. For liabilities payable to employees, the Company accounts for the liability in accordance with Financial Accounting Stands Board (“FASB”) Accounting Stand Codification (“ASC”) 450 Contingencies.
Property and Equipment	Property and Equipment
	Property and equipment are stated at cost, net of accumulated depreciation and amortization. All property and equipment is depreciated on a straight-line basis over the following estimated useful lives:


	Computer and office equipment		3 – 5 years
	Software		3 years
	Furniture and fixtures		3 years
	Leasehold improvements are amortized over the lesser of their useful life or the term of the applicable lease. Upon sale or retirement of assets, the cost and related accumulated depreciation and amortization are removed from the consolidated balance sheet and the resulting gain or loss is reflected in operations. Maintenance and repairs are charged to operations as incurred.
2012 Reverse Stock Split	2012 Reverse Stock Split
	The Company effected a 1-for-6.09 reverse stock split of its common stock and preferred stock on July 12, 2012. Accordingly, all share and per share amounts for all periods presented in these consolidated financial statements and notes thereto, have been adjusted retroactively to reflect this reverse stock split.
Preclinical and Clinical Trial Accruals	Preclinical and Clinical Trial Accruals
	The Company’s clinical trial accruals are based on estimates of patient enrollment and related costs at clinical investigator sites as well as estimates for the services received and efforts expended pursuant to contracts with multiple research institutions and clinical research organizations that conduct and manage preclinical and clinical trials on the Company’s behalf. The Company accrues expenses related to clinical trials based on contracted amounts applied to the level of patient enrollment and activity according to the protocol. If timelines or contracts are modified based upon changes in the clinical trial protocol or scope of work to be performed, the Company modifies the estimates of accrued expenses accordingly. To date, the Company has had no significant adjustments to accrued preclinical and clinical trial expenses.
Revenue Recognition	Revenue Recognition
	The Company recognizes revenue in accordance with ASC 605, Revenue Recognition, when the following criteria have been met: persuasive evidence of an arrangement exists; delivery has occurred and risk of loss has passed; the seller’s price to the buyer is fixed or determinable and collectability is reasonably assured. The Company determines that persuasive evidence of an arrangement exists based on written contracts that defined the terms of the arrangements. In addition, the Company determines that services have been delivered in accordance with the arrangement. The Company assesses whether the fee is fixed or determinable based on the payment terms associated with the transaction and whether the sales price is subject to refund or adjustment. The Company assesses collectability based primarily on the customer’s payment history and on the creditworthiness of the customer.
	Product Revenue, net: The Company’s product revenue represents sales of RAVICTI and BUPHENYL which are recognized once all four revenue recognition criteria described above are met. The Company recognizes revenue net of product sales allowances. Product shipping and handling costs are included in cost of sales. Prior to June 2014, revenue from the sale of RAVICTI was recognized based on the amount of product sold through to the end user consumer. Starting June 2014, the Company could reasonably estimate and determine sales allowances, therefore the Company began recognizing RAVICTI revenue at the point of sale to the specialty distributor, which resulted in the one-time non-recurring recognition of an additional $8.6 million in net revenues during the year ended December 31, 2014. The impact of this change resulted in a decrease in net loss of $7.9 million for year ended December 31, 2014, or $0.39 per basic and diluted share.
	Product Sales Allowances: The Company establishes reserves for prompt-payment discounts, government and commercial rebates, product returns and chargebacks. Allowances relate to prompt-payment discounts and are recorded at the time of revenue recognition, resulting in a reduction in product sales revenue and a decrease in trade accounts receivables. Accruals related to government rebates, product returns and other applicable allowances such as distributor fees are recognized at the time of revenue recognition, resulting in a reduction in product sales and an increase in accrued expenses or a reduction in the related accounts receivable.

		•	Prompt-payment discounts: The specialty distributor and specialty pharmacies are offered prompt payment discounts. The Company expects the specialty distributor and specialty pharmacies will earn prompt payment discounts and, therefore deduct the full amount of these discounts from total product sales when revenues are recognized. The Company records prompt-payment discounts as allowances against accounts receivable on the consolidated balance sheets.

		•	Rebates: Allowances for rebates include mandated discounts under the Medicaid Drug Rebate Program. Rebate amounts are based upon contractual agreements or legal requirements with public sector (e.g. Medicaid) benefit providers. Rebates are amounts owed after the final dispensing of the product to a benefit plan participant and are based upon contractual agreements or legal requirements with public sector benefit providers. The allowance for rebates is based on statutory discount rates and expected utilization. The Company estimates for expected utilization of rebates based on historical data and data received from the specialty pharmacies. Rebates are generally invoiced and paid in arrears so that the accrual balance consists of an estimate of the amount expected to be incurred for the current quarter’s activity, plus an accrual balance for known prior quarter’s unpaid rebates. If actual future rebates vary from estimates, the Company may need to adjust prior period accruals, which would affect revenue in the period of adjustment. Allowance for rebates are recorded in accrued liabilities on the consolidated balance sheets.

		•	Chargebacks: Chargebacks are discounts that occur when contracted customers purchase directly from a specialty distributor. Contracted customers, which primarily consist of Public Health Service institutions, non-profit clinics, and Federal government entities purchasing via the Federal Supply Schedule, generally purchase the product at a discounted price. The specialty distributor, in turn, charges back to the Company the difference between the price initially paid by the specialty distributor and the discounted price paid to the specialty distributor by the customer. The allowance for chargebacks is based on historical sales data and known sales to contracted customers.

		•	Medicare Part D Coverage Gap: Medicare Part D prescription drug benefit mandates manufacturers to fund 50% of the Medicare Part D insurance coverage gap for prescription drugs sold to eligible patients. The Company estimates for the expected Medicare Part D coverage gap are based on historical invoices received and in part from data received from the specialty pharmacies. Funding of the coverage gap is generally invoiced and paid in arrears so that the accrual balance consists of an estimate of the amount expected to be incurred for the current quarter’s activity, plus an accrual balance for known prior quarters. If actual future funding varies from estimates, the Company may need to adjust prior period accruals, which would affect revenue in the period of adjustment. Estimates of the Medicare Part D coverage gap are recorded in accrued liabilities on the consolidated balance sheets.

		•	Distribution Service Fees: The Company has a written contract with the specialty distributor that includes terms for distribution-related fees. Distributor fees are calculated at percentage of gross sales based upon agreed contracted rate. The Company accrues distributor fees at the time of the revenue recognition, resulting in reduction of product sales revenue and the recording of accrued liabilities on the consolidated balance sheets. The Company records distribution and other fees paid to its customers as a reduction of revenue, unless it receives an identifiable and separate benefit for the consideration and it can reasonably estimate the fair value of the benefit received. If both conditions are met, the Company records the consideration paid to the customer as an operating expense. These costs are typically known at the time of sale.

		•	Product Returns: Consistent with industry practice, the Company generally offers customers a limited right to return. The Company accepts returns of products from patients resulting from breakage as defined within the Company’s returns policy. Additionally, the Company considers several other factors in the estimation process including the expiration dates of product shipped, third party data in monitoring channel inventory levels, shelf life of the product, prescription trends and other relevant factors. Provisions for estimated product returns are recorded as accrued liabilities on the consolidated balance sheets.

		•	Co-payment assistance: The Company provides a cash donation to a non-profit third party organization which supports patients, who have commercial insurance and meet certain financial eligibility requirements, with co-payment assistance and travel costs. The amount of co-payment assistance is accounted for by the Company as a reduction of revenues.
Cost of sales	Cost of sales
	Cost of sales includes third-party manufacturing cost of products sold, royalty fees, and other indirect costs related to personnel compensation, shipping and supplies. Costs incurred prior to FDA approval of RAVICTI have been recorded as research and development expense in the Company’s consolidated statement of operations. The Company expects that cost of RAVICTI sales as a percentage of revenue will increase in future periods as product manufactured prior to FDA approval, and therefore fully expensed, has been utilized. Cost of BUPHENYL sales for 2013 as a percentage of revenue was higher and not indicative of cost of sales in future periods due to the recording of the step-up value on BUPHENYL inventories acquired from Ucyclyd which is expensed to cost of sales as that inventory is sold. As of December 31, 2014, the entire fair value of acquired BUPHENYL inventory has been charged to expense, primarily cost of sales.
Foreign Currency Translations	Foreign Currency Translations
	Operations in non-U.S. entities are recorded in the functional currency of each entity. For financial reporting purposes, the functional currency of an entity is determined by a review of the source of an entity’s most predominant cash flows. The reporting and functional currency of the Company and its subsidiaries is the U.S. dollar.
	Gains and losses resulting from foreign currency transactions are translated at the weighted average rate of exchange prevailing during the period. Any monetary asset or liability denominated in foreign currency and is translated at the rate of exchange in effect on the balance sheet date. Any gains and losses resulting from foreign currency translations are included in other income (expense)-net in the consolidated statements of operations. The Company does not currently utilize and has not in the past utilized any foreign currency hedging strategies to mitigate the effect of its foreign currency exposure.
Research and Development Expenses	Research and Development Expenses
	Costs related to research and development of products are charged to expense as incurred. Research and development costs include, but are not limited to, payroll and personnel expenses, clinical trial supplies, fees for clinical trial services, consulting costs and allocated overhead, including rent, equipment, depreciation and utilities.
Stock-Based Compensation	Stock-Based Compensation
	The Company accounts for stock-based employee compensation arrangements in accordance with provisions of ASC 718, Compensation — Stock Compensation. ASC 718 requires the recognition of compensation expense, using a fair-value based method, for costs related to all share-based payments including stock options. ASC 718 requires companies to estimate the fair value of share-based payment awards on the date of grant using an option-pricing model. The Company calculates the fair value of stock options using the Black-Scholes method and expenses using the straight-line attribution approach.
Income Taxes	Income Taxes
	The Company accounts for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized.
	The Company accounts for uncertain tax positions in accordance with ASC 740-10, Accounting for Uncertainty in Income Taxes. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the position’s sustainability and is measured at the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. As of each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized tax benefit is still appropriate. The recognition and measurement of tax benefits requires significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available.
Comprehensive Income (Loss)	Comprehensive Income (Loss)
	Comprehensive income (loss) is comprised of net income (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.
Net Income (Loss) per Share of Common Stock	Net Income (Loss) per Share of Common Stock
	Basic earnings per share is computed by dividing the net income (loss) by the weighted average number of shares of common stock outstanding during the periods presented. The computation of diluted earnings per share is similar to the computation of basic earnings per share, except that the denominator is increased for the assumed exercise of dilutive options and other potentially dilutive securities using the treasury stock method, unless the effect is antidilutive.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In July 2013, FASB issued ASU No. 2013-11, Income Taxes (Topic 740): Presentation of an unrecognized tax benefit when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists. Under the amendments of this update an entity is required to present an unrecognized tax benefit, or a portion of an unrecognized tax benefit in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except as follows. To the extent a net operating loss carryforward, a similar tax loss, or a tax credit carryforward is not available at the reporting date under the tax law of the applicable jurisdiction to settle any additional income taxes that would result from the disallowance of a tax position or the tax law of the applicable jurisdiction does not require the entity to use, and the entity does not intend to use, the deferred tax asset for such purpose, the unrecognized tax benefit should be presented in the financial statements as a liability and should not be combined with deferred tax assets. The assessment of whether a deferred tax asset is available is based on the unrecognized tax benefit and deferred tax asset that exist at the reporting date and should be made presuming disallowance of the tax position at the reporting date. For example, an entity should not evaluate whether the deferred tax asset expires before the statute of limitations on the tax position or whether the deferred tax asset may be used prior to the unrecognized tax benefits being settled. The provisions of this update was effective prospectively for the Company in fiscal years beginning after December 15, 2013 with early adoption and retrospective application permitted. The Company adopted this guidance on January 1, 2014. The implementation did not have an impact on the Company’s consolidated financial statements.
	In May 2014, FASB issued Accounting Standards Update 2014-09 (ASU 2014-09), Revenue from Contracts with Customers. ASU 2014-09 will supersede the revenue recognition requirements in Revenue Recognition (Topic 605) and requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period, which for the Company is January 1, 2017. Early adoption is not permitted. The Company is currently evaluating the potential impact the adoption of ASU 2014-09 will have on the Company’s consolidated financial statements.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
Summary of Significant Accounting Policies (Tables)	Dec. 31, 2014
Accounting Policies [Abstract]
Schedule of Property and Equipment Estimated Useful Lives	All property and equipment is depreciated on a straight-line basis over the following estimated useful lives:


	Computer and office equipment	3 – 5 years
	Software	3 years
	Furniture and fixtures	3 years

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
Acquisitions (Tables)	Dec. 31, 2014
Schedule of Purchase Price Allocation	The following table summarizes the allocation of purchase price to the fair values of the assets acquired as of the acquisition date:


			(in thousands)
	Inventories		$	3,900
	Intangible Asset — BUPHENYL Product rights			16,500

	Total		$	20,400

Total Gain from Buphenyl Acquisition	The following table summarizes the results of the Company’s allocation:


			(in thousands)
	Ucyclyd’s retention option amount		$	32,000
	Amount due to Ucyclyd for BUPHENYL product rights			(19,000	)
	Amount due to Ucyclyd for inventory			(2,038	)

	Net payment received from Ucyclyd			10,962
	Option to purchase the rights to BUPHENYL and AMMONUL			(283	)
	Fair value of BUPHENYL			20,400

	Gain from settlement of retention option		$	31,079

Consolidated Pro Forma Information	In addition, the unaudited pro forma information does not purport to project the future results of operations of the Company.


			Year Ended
			December 31,
			2014			2013			2012
						( in thousands)
	Net revenues		$	113,584		$	52,900		$	21,501
	Net income (loss)			20,390			(12,199	)		(29,201	)
	Net income (loss) per common share
	Basic			0.99			(0.62	)		(4.02	)
	Diluted			0.93			(0.62	)		(4.02	)

Andromeda
Consideration for Acquisition Transferred	The Acquisition Date fair value of the total consideration transferred to acquire Andromeda was as follows:


			Amounts Recognized as
			of the acquisition date
			(in thousands)
	Cash paid		$	14,345
	Fair value of Company’s common stock issued (312,869 shares)			7,778	*
	Acquisition-related contingent consideration			68,961

	Total fair value of consideration transferred		$	91,084


	*	The fair value of the common stock was measured using the Company’s closing stock price on June 12, 2014.
Allocation of Purchase Price to the Fair Values of Assets Acquired and Liabilities Assumed	The following table summarizes the provisional allocation of purchase price to the fair values of the assets acquired and liabilities assumed as of the acquisition date:


			Amounts Recognized as
			of the acquisition date
			(in thousands)
	Assets acquired
	IPR&D		$	135,712
	Cash and cash equivalents			306
	Prepaid expenses			95
	Property and equipment, net			22
	Other assets			578
	Liabilities assumed
	Current liabilities			(9,079	)
	Deferred tax liability			(6,051	)
	Acquisition related contingent liability			(34,288	)

	Total identifiable net assets			87,295
	Goodwill			3,789

	Total consideration transferred		$	91,084

Measurement Period Adjustments
Consideration for Acquisition Transferred	Adjusted Fair Value of Consideration Transferred


			Amounts Recognized
			as of September 30,
			2014 (as adjusted)
			(in thousands)
	Cash paid		$	14,345
	Fair value of Company’s common stock issued (312,869 shares)			7,778
	Acquisition-related contingent consideration			—	*

	Total fair value of consideration transferred		$	22,123


	*	The Company has assigned no value to the IPR&D as a result of the evidence obtained related to the improper practices regarding the clinical trials. The Company had determined that the contingent consideration milestones and contingent liability milestones will not be achieved.

	**	The reduction in deferred tax liability relates to the tax impact of the IPR&D and acquisition- related contingencies.
Allocation of Purchase Price to the Fair Values of Assets Acquired and Liabilities Assumed	The following table summarizes the adjusted provisional allocation of purchase price to the fair values of the assets acquired and liabilities assumed as of the Acquisition Date:


			Amounts Recognized
			as of September 30,
			2014 (as adjusted)
			(in thousands)
	Assets acquired
	IPR&D		$	—	*
	Cash and cash equivalents			306
	Prepaid expenses			95
	Property and equipment, net			22
	Other assets			578
	Liabilities assumed
	Current liabilities			(9,079	)
	Deferred tax liability			—	**
	Acquisition related contingent liability			—	*

	Total identifiable net assets (liabilities)			(8,078	)
	Adjusted Goodwill			30,201

	Total consideration transferred		$	22,123

Investments_Tables

Investments (Tables)	12 Months Ended
Investments (Tables)	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Schedule of Investments by Contractual Maturity	The principal amounts of investments by contractual maturity at December 31, 2014 and December 31, 2013 are summarized in the tables below:


		Contractual Maturity Date for the					Total Book		Unrealized			Aggregate
		Years Ending December 31,					Value at		Loss			Fair Value at
							December 31, 2014					December 31, 2014
		2015		2016
	Certificates of deposit	$	18,405	$	6,240		$	24,645	$	(35	)	$	24,610
	Corporate notes		12,613		3,011			15,624		(12	)		15,612
	Commercial paper		3,494		—			3,494		(3	)		3,491

	Total	$	34,512	$	9,251		$	43,763	$	(50	)	$	43,713



		Contractual Maturity Date for the					Total Book		Unrealized			Aggregate
		Years Ending December 31,					Value at		Loss			Fair Value at
							December 31, 2013					December 31, 2013
		2014		2015
	Certificates of deposit	$	10,525	$	2,845		$	13,370	$	(27	)	$	13,343
	Corporate notes		6,047		12,960			19,007		(24	)		18,983
	U.S. Government agency securities		8,011		—			8,011		(3	)		8,008
	Commercial paper		3,492		—			3,492		(1	)		3,491

	Total	$	28,075	$	15,805		$	43,880	$	(55	)	$	43,825

Schedule of Unrealized Losses and Related Fair Value of Investments with Unrealized Losses	The aggregate amounts of unrealized losses and related fair value of investments with unrealized losses as of December 31, 2014 and December 31, 2013 was as follows:


		Less Than 12 Months to					12 Months or More to					Total at December 31, 2014
		Maturity					Maturity					Total at December 31, 2014
		Aggregate		Unrealized			Aggregate		Unrealized			Aggregate		Unrealized
		Fair Value		Losses			Fair Value		Losses			Fair Value		Losses
	Certificates of deposit	$	18,386	$	(19	)	$	6,224	$	(16	)	$	24,610	$	(35	)
	Corporate notes		12,610		(2	)		3,002		(10	)		15,612		(12	)
	Commercial paper		3,491		(3	)		—		—			3,491		(3	)

	Total	$	34,487	$	(24	)	$	9,226	$	(26	)	$	43,713	$	(50	)



		Less Than 12 Months to					12 Months or More to					Total at December 31, 2013
		Maturity					Maturity					Total at December 31, 2013
		Aggregate		Unrealized			Aggregate		Unrealized			Aggregate		Unrealized
		Fair Value		Losses			Fair Value		Losses			Fair Value		Losses
	Certificates of deposit	$	10,507	$	(18	)	$	2,836	$	(9	)	$	13,343	$	(27	)
	Corporate notes		6,039		(8	)		12,944		(16	)		18,983		(24	)
	U.S. Government agency securities		8,008		(3	)		—		—			8,008		(3	)
	Commercial paper		3,491		(1	)		—		—			3,491		(1	)

	Total	$	28,045	$	(30	)	$	15,780	$	(25	)	$	43,825	$	(55	)

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
Fair Value Measurements (Tables)	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis	The following table presents the Company’s fair value hierarchy for assets and liabilities measured at fair value on a recurring basis as of December 31, 2014 and December 31, 2013 (in thousands):


		Fair Value Measurements at December 31, 2014
		Quoted Price in		Significant Other		Significant		Total
		Active Markets		Observable Inputs		Unobservable
		for Identical Assets		(Level 2)		Inputs
		(Level 1)				(Level 3)
	Assets:
	Cash equivalents:
	Money market funds	$	38,532	$	—	$	—	$	38,532
	Certificates of deposit		—		720		—		720

	Total cash equivalents	$	38,532	$	720	$	—	$	39,252

	Available-for-sale securities:
	Short-term:
	Certificates of deposit	$	—	$	18,386	$	—	$	18,386
	Corporate notes		—		12,610		—		12,610
	Commercial paper		—		3,491		—		3,491

	Total short-term investments		—		34,487		—		34,487

	Long-term:
	Certificates of deposit		—		6,224		—		6,224
	Corporate notes		—		3,002		—		3,002

	Total long-term investments		—		9,226		—		9,226

	Total available-for-sale securities	$	—	$	43,713	$	—	$	43,713



		Fair Value Measurements at December 31, 2013
		Quoted Price in		Significant Other		Significant		Total
		Active Markets		Observable Inputs		Unobservable
		for Identical Assets		(Level 2)		Inputs
		(Level 1)				(Level 3)
	Assets:
	Cash equivalents:
	Money market funds	$	38,506	$	—	$	—	$	38,506
	Certificates of deposit		—		480		—		480

	Total cash equivalents	$	38,506	$	480	$	—	$	38,986

	Available-for-sale securities:
	Short-term:
	Certificates of deposit	$	—	$	10,507	$	—	$	10,507
	Commercial paper		—		3,491		—		3,491
	Corporate notes		—		6,039		—		6,039
	U.S. Government agency securities		—		8,008		—		8,008

	Total short-term investments		—		28,045		—		28,045

	Long-term:
	Certificates of deposit		—		2,836		—		2,836
	Corporate notes		—		12,944		—		12,944

	Total long-term investments		—		15,780		—		15,780

	Total available-for-sale securities	$	—	$	43,825	$	—	$	43,825

Carrying Value and Estimated Fair Value of Company's Notes Payable and Term Loans	The following table presents the carrying value and estimated fair value of the Company’s notes payable as of December 31, 2014 and December 31, 2013 (in thousands):


		December 31, 2014
		Carrying		Estimated
		Value		Fair Value
	Term Loans (see Note 11)	$	16,124	$	16,746


		December 31, 2013
		Carrying		Estimated
		Value		Fair Value
	April and September 2012 Notes (see Note 11)	$	8,273	$	8,860

Inventories_Tables

Inventories (Tables)	12 Months Ended
Inventories (Tables)	Dec. 31, 2014
Inventory Disclosure [Abstract]
Components of Inventories	The following table represents the components of inventories, net of reserves (in thousands):


		December 31,		December 31,
		2014		2013
	Raw Materials	$	1,787	$	697
	Work-in-process		543		—
	Finished goods		2,291		2,816

	Total	$	4,621	$	3,513

Intangible_Assets_and_Goodwill1

Intangible Assets and Goodwill (Tables)	12 Months Ended
Intangible Assets and Goodwill (Tables)	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Expected Amortization Expense	Estimated aggregate amortization expense for each of the five succeeding years ending December 31 is as follows (in thousands):


		2015		2016		2017		2018		2019
	Amortization expense	$	6,495	$	1,655	$	1,515	$	1,477	$	1,441

Property_and_Equipment_Tables

Property and Equipment (Tables)	12 Months Ended
Property and Equipment (Tables)	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Components of Property and Equipment	The following table represents the components of property and equipment (in thousands):


		December 31,
		2014			2013
	Computers and Software	$	1,202		$	563
	Furniture and Fixtures		320			320
	Office Equipment		53			53
	Leasehold Improvements		—			—
	Capital work in progress		181			264

			1,756			1,200
	Less: Accumulated depreciation		(640	)		(264	)

	Total property and equipment, net	$	1,116		$	936

Accrued_Liabilities_Tables

Accrued Liabilities (Tables)	12 Months Ended
Accrued Liabilities (Tables)	Dec. 31, 2014
Payables and Accruals [Abstract]
Components of Accrued Liabilities	The following table represents the components of accrued liabilities (in thousands):


		December 31,
		2014		2013
	Clinical trial expenses	$	2,399	$	246
	Payroll and related expenses		4,134		4,278
	Gross to net sales accruals		10,142		5,235
	Royalty payable		2,080		1,154
	Taxes payable		563		326
	Legal expenses payable		410		45
	Acquisition related accrual (Note 22)		4,615		—
	Other		1,166		903

		$	25,509	$	12,187

Notes_Payable_Tables

Notes Payable (Tables)	12 Months Ended
Notes Payable (Tables)	Dec. 31, 2014
Debt Disclosure [Abstract]
Future Minimum Payments Under Loan Agreement	Future minimum payments under the Loan Agreement as of December 31, 2014 are as follows (in thousands):


	Years Ending December 31,
	2015	$	730
	2016		6,822
	2017		8,786
	2018		4,450

	Total future minimum payments	$	20,788
	Less: amount representing unamortized interest		(1,709	)
	Less: amount representing debt discount		(955	)

	Total minimum payments	$	18,124
	Less: current portion		—

	Non-current portion	$	18,124

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
Commitments and Contingencies (Tables)	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Lease Payments	Aggregate total future minimum lease payments under operating facility and equipment leases as of December 31, 2014 were as follows (in thousands):


	Years Ending December 31,
	2015	$	797
	2016		820
	2017		821
	2018		845
	2019		766

	Total	$	4,049

Common_Stock_Tables

Common Stock (Tables)	12 Months Ended
Common Stock (Tables)	Dec. 31, 2014
Text Block [Abstract]
Common Stock Reserved for Future Issuances	At December 31, 2014, the Company had reserved common stock for future issuances as follows:


	Issuance of options under 2012 stock plan	688,842
	Issuance upon exercise of options under the 2006 and 2012 stock plan	3,068,741
	Issuance upon vesting of restricted and performance stock units under the 2012 stock plan	136,293
	Issuance upon exercise of October 2007 common stock warrants	274

	Total	3,894,150

Stock_Option_Plan_Tables

Stock Option Plan (Tables)	12 Months Ended
Stock Option Plan (Tables)	Dec. 31, 2014
Weighted-Average Assumptions for Fair Value of Stock Options	The fair value of the employee stock options was estimated using the following weighted-average assumptions:


		Year Ended December 31,
		2014			2013			2012
	Expected volatility		62.76	%		58	%		65	%
	Risk-free interest rate		1.9	%		1.14	%		1.05	%
	Dividend yield		0	%		0	%		0	%
	Expected term (in years)		6			5.96			6
Allocation of Stock-Based Compensation Expense	Total stock-based compensation expense related to options and awards granted was allocated as follows (in thousands):


		Year Ended December 31,
		2014			2013			2012
	Cost of sales	$	70		$	27		$	—
	Research and development		1,384			585			374
	Selling general and administrative		6,184			3,709			619

	Total	$	7,638		$	4,321		$	993

2006 Plan
Schedule of Option Activity	Activity under the 2006 Plan is as follows:


					Outstanding Options
		Number of Shares			Number of Shares			Weighted-Average
		Available for			Underlying			Exercise Price Per
		Grant			Outstanding			Share
					Options
	Balances at December 31, 2013		—			1,538,197			3.64
	Options exercised		—			(190,263	)		3.73
	Options cancelled		14,413			(14,413	)		6.78
	Options re-allocated to 2012 Plan		(14,413	)		—			—

	Balances at December 31, 2014		—			1,333,521		$	3.6

Aggregate Options Outstanding and Vested and Exercisable by Exercise Price	Aggregate options outstanding and vested and exercisable by exercise price at December 31, 2014 for the 2006 plan are as follows (dollars in thousands except per share values):


	Options Outstanding										Options Vested and Exercisable
	Exercise	Number			Aggregate			Weighted			Number			Aggregate		Exercise
	Price	Outstanding			Intrinsic			Average			Outstanding			Intrinsic		Price
					Value			Remaining						Value
								Life (in Years)
	$ 1.28		735,773		$	16,717			4.5			735,773		$	16,717	$	1.28
	$ 4.08		252,403			5,028			6.3			228,490			4,552	$	4.08
	$ 7.31		344,405			5,748			7.3			217,060			3,623	$	7.31
	$ 327.95		940			—			2.5			940			—	$	327.95

			1,333,521		$	27,493			5.5			1,182,263		$	24,892

2012 Plan
Schedule of Option Activity	Activity under the 2012 Plan is as follows:


					Outstanding Options						Restricted Stock Units					Performance Stock Units
					Outstanding Options						Outstanding					Outstanding
		Number of Shares			Number of Shares			Weighted-Average			Number of Shares			Grant		Number of Shares		Grant
		Available for			Underlying			Exercise Price Per			Underlying			Date		Underlying		Date
		Grant			Outstanding			Share			Outstanding			Fair Value		Outstanding		Fair Value
					Options						RSU’s					RSU’s
	Balances at December 31, 2013		576,760			1,252,433			20.75			18,000			19.39		—		—
	Additional shares authorized		805,485			—			—			—			—		—		—
	Options and awards granted		(938,062	)		806,919			25.99			122,155			26.68		8,988		25.08
	Options exercised		—			(101,736	)		18.42			—			—		—		—
	Awards released		—			—			—			(5,000	)		20.13		—		—
	Options re-allocated to 2012 Plan		14,413			—			—			—			—		—		—
	Options and awards cancelled		230,246			(222,396	)		22.66			(7,850	)		26.74		—		—

	Balance at December 31, 2014		688,842			1,735,220		$	23.08			127,305		$	25.9		8,988	$	25.08

Aggregate Options Outstanding and Vested and Exercisable by Exercise Price	Aggregate options outstanding and vested and exercisable by exercise price at December 31, 2014 for the 2012 plan are as follows (dollars in thousands except per share values):


		Options Outstanding									Options Vested and Exercisable
	Exercise Price	Number			Aggregate			Weighted			Number			Aggregate		Exercise
		Outstanding			Intrinsic			Average			Outstanding			Intrinsic		Price
					Value			Remaining						Value
								Life (in Years)
	$10.32- 18.24		242,962		$	2,799			7.9			118,837		$	1,415	$	10.32 - 18.24
	$19.39- 21.05		200,170			746			9			36,504			162		19.39 - 21.05
	$21.45- 24.38		128,450			220			8.7			41,514			83		21.45 - 24.38
	$24.46- 26.74		1,095,725			—			8.8			253,207			—		24.46 - 26.74
	$26.97- 28.08		42,313			—			9.3			—			—		26.97 - 28.08
	$29.27- 31.00		25,600			—			9.3			—			—		29.27 - 31.00

			1,735,220		$	3,765			8.7			450,062		$	1,660

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Components of Income Tax Expense	The components of the income tax expense are as follows (in thousands):


		Years ended
		December 31,
		2014			2013			2012
	Current income tax expense:
	Federal	$	736		$	—		$	—
	State		703			326			—

			1,439			326			—

	Deferred income tax benefit:
	State		(1,136	)		(277	)		—

			(1,136	)		(277	)		—

	Total income tax expense	$	303		$	49		$	—

Reconciliation of Income Tax Expense	The reconciliation of income tax expense computed at the statutory federal income tax rate of 35% to amounts included in the consolidated statements of operations is as follows:


		Year Ended December 31,
		2014			2013			2012
	Statutory rate		35	%		35	%		34	%
	State tax		0.6	%		5.5	%		5.4	%
	Tax credits		57.5	%		(5.0	)%		0.7	%
	Stock options		(28.0	)%		0.2	%		(0.7	)%
	Valuation allowance		(81.8	)%		(29.6	)%		(37.1	)%
	Impact of Andromeda acquisition		12.6	%		—			—
	Change in federal tax rate		—			(6.0	)%		—
	Other		(1.0	)%		0.2	%		(2.3	)%

			(5.1	)%		0.3	%		0	%

Components of Deferred Income Tax Assets	Significant components of the Company’s deferred income tax assets are as follows (in thousands):


		Year Ended December 31,
		2014			2013
	Deferred income tax assets
	Fixed assets, capitalized intangibles and other assets	$	6,030		$	5,294
	Net operating loss		35,164			31,842
	Tax credits		23,024			18,480
	Stock-based compensation expense		1,660			1,133
	Accrued expenses and reserves		3,405			1,502
	Capitalized research and development expenses		3,237			—
	Tax basis in investments		12,624			—
	Other		381			25

	Total		85,525			58,276
	Valuation allowance		(84,113	)		(58,000	)

	Net deferred income tax assets	$	1,412		$	276

Reconciliation of Beginning and Ending Balances of Unrecognized Income Tax Benefits	A reconciliation of the beginning and ending balances of the unrecognized income tax benefits during the years ended December 31, 2014, 2013 and 2012 is as follows (in thousands):


		Year Ended December 31,
		2014			2013			2012
	Balance at the beginning of the year	$	6,269		$	5,723		$	5,357
	Changes based on prior period tax positions		(2,325	)		—			(228	)
	Changes based on current period tax positions		223			546			594

	Balance at the end of the year	$	4,167		$	6,269		$	5,723

Net_Income_Loss_per_Share_of_C1

Net Income (Loss) per Share of Common Stock (Tables)	12 Months Ended
Net Income (Loss) per Share of Common Stock (Tables)	Dec. 31, 2014
Earnings Per Share [Abstract]
Net Income (Loss) Per Share of Common Stock	The following table sets forth the computation of basic and diluted net income (loss) per share of common stock for the periods indicated (in thousands, except share and per share amounts):


		Year Ended December 31,
		2014			2013		2012
	Net income (loss) per share
	Numerator:
	Net income (loss) attributable to common stockholders	$	(6,255	)	$	16,627	$	(32,263	)

	Denominator:
	Weighted-average number of common shares outstanding — basic		20,470,025			19,415,822		7,256,537
	Dilutive effect of stock-options and awards		—			1,315,091		—

	Weighted average common shares outstanding — dilutive		20,470,025			20,730,913		7,256,537

	Net income (loss) per share:
	Basic	$	(0.31	)	$	0.86	$	(4.45	)

	Diluted	$	(0.31	)	$	0.8	$	(4.45	)

Antidilutive Securities Excluded from Computation of Earnings Per Share	The following outstanding potentially dilutive securities were excluded from the computation of diluted net income (loss) per share, as the effect of including them would have been antidilutive:


		Year Ended December 31,
		2014			2013		2012
	Stock options		3,068,741			1,027,605		1,928,754
	Common stock warrants		274			274		84,656

	Total		3,069,015			1,027,879		2,013,410

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
Segment Reporting (Tables)	Dec. 31, 2014
Segment Reporting [Abstract]
Net Product Revenue for Ravicti and Buphenyl	Net product revenue for RAVICTI and BUPHENYL for the years ended December 31, 2014 and 2013 are as follows (in thousands):


		Year Ended
		December 31,
		2014			2013
	RAVICTI	$	95,400		$	31,236
	BUPHENYL		18,584			11,468
	Co-payment assistance		(400	)		(500	)

	Total	$	113,584		$	42,204

Net Product Revenue for Ravicti and Buphenyl by Geographic Region	Net product revenue for RAVICTI and BUPHENYL by geographic region are as follows (in thousands):


		Year Ended
		December 31,
		2014			2013
	United States	$	103,303		$	37,102
	Canada		3,723			2,208
	Rest of the world		6,558			2,894

	Total	$	113,584		$	42,204

Selected_Quarterly_Financial_D1

Selected Quarterly Financial Data (Tables)	12 Months Ended
Selected Quarterly Financial Data (Tables)	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Selected Unaudited Quarterly Financial Information	The following table presents selected unaudited quarterly financial information for the years ended December 31, 2014, 2013 and 2012. 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 Quarters Ended
	(in thousands, except share and per share amounts)		December 31,		September 30,⁽¹⁾			June 30,		March 31,
	Year Ended December 31, 2014
	Product revenue, net		$	30,805	$	26,201		$	37,095	$	19,483
	Costs and expenses		$	24,078	$	55,031		$	20,898	$	17,784
	Net income (loss) attributable to common stockholders		$	7,096	$	(32,793	)	$	18,183	$	1,259
	Net income (loss) per share attributable to common stockholders — basic		$	0.34	$	(1.59	)	$	0.89	$	0.06
	Net income (loss) per share attributable to common stockholders — diluted		$	0.32	$	(1.59	)	$	0.84	$	0.06

			For The Quarters Ended
	(in thousands, except share and per share amounts)		December 31,		September 30,			June 30,⁽²⁾		March 31,
	Year Ended December 31, 2013
	Product revenue, net		$	18,627	$	15,489		$	7,305	$	783
	Costs and expenses		$	17,747	$	15,037		$	12,986	$	9,851
	Net income (loss) attributable to common stockholders		$	468	$	112		$	25,022	$	(8,975	)
	Net income (loss) per share attributable to common stockholders — basic		$	0.02	$	0.01		$	1.25	$	(0.52	)
	Net income (loss) per share attributable to common stockholders — diluted		$	0.02	$	0.01		$	1.17	$	(0.52	)

	-1	For the quarter ended September 30, 2014, the Company recorded $30.2 million as an impairment charge of goodwill on the Company’s consolidated statements of operations. Also refer to the information contained in Note 4 of the consolidated financial statements appearing elsewhere in the report.

	-2	For the quarter ended June 30, 2013, the Company recorded a gain of $31.1 million related to the BUPHENYL acquisition on the consolidated statements of operations. Also refer to the information contained in Note 4 of the consolidated financial statements appearing elsewhere in the report.

Formation_and_Business_of_the_1

Formation and Business of the Company - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended
	Jul. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 13, 2013	Aug. 14, 2013
Nature Of Operations [Line Items]
Offering price per share	$10
Additional shares issued for over-allotment	750,000
Net proceeds from initial public offering				$53,475,000
Underwriting discounts and commissions			4,116,000	4,025,000
Net proceeds from public offering			64,488,000
Aggregate offering price						150,000,000
Common stock shares sold by selling stockholders						8,727,000
Aggregate offering price under sales agreement						50,000,000
Sales of securities		0
Income (loss) from operations		-4,207,000	-13,417,000	-28,533,000
Accumulated deficit		-128,625,000	-122,370,000
April 2011 Convertible Notes Payable
Nature Of Operations [Line Items]
Principal and accrued interest converted upon closing of IPO	18,900,000
Number of shares issued upon conversion of notes	1,888,054
Carrying value and accrued interest	18,400,000
October 2011 Convertible Notes Payable
Nature Of Operations [Line Items]
Principal and accrued interest converted upon closing of IPO	15,600,000
Number of shares issued upon conversion of notes	1,556,816
Carrying value and accrued interest	14,900,000
Series C-1 Convertible Preferred Stock
Nature Of Operations [Line Items]
Preferred stock converted into common stock	1,912,598
Series C-2 Convertible Preferred Stock
Nature Of Operations [Line Items]
Preferred stock converted into common stock	4,663,039
April 2011 Common Stock Warrants Liability
Nature Of Operations [Line Items]
Shares issued for conversion of warrants upon closing of IPO	322,599
October 2011 Preferred Stock Warrants Liability
Nature Of Operations [Line Items]
Shares issued for conversion of warrants upon closing of IPO	17,762
Initial Public Offering
Nature Of Operations [Line Items]
Common stock, shares issued	5,000,000
Net proceeds from initial public offering	51,300,000
Underwriting discounts and commissions	4,025,000
Other offering expenses	2,200,000
Follow-on offering
Nature Of Operations [Line Items]
Common stock, shares issued					2,875,000
Offering price per share					$20.75
Additional shares issued for over-allotment					431,250
Underwriting discounts and commissions					4,116,000
Other offering expenses					800,000
Net proceeds from public offering					$63,700,000
BUPHENYL
Nature Of Operations [Line Items]
Business acquisition date		31-May-13
Andromeda
Nature Of Operations [Line Items]
Business acquisition date		12-Jun-14

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
	Jul. 12, 2012	Dec. 31, 2014	Dec. 31, 2013
Summary Of Significant Accounting Policies [Line Items]
Credit losses on investments		$0
Allowances for doubtful accounts		0
Reverse stock split	1-for-6.09
Reverse stock split ratio	6.09
Adjustments to accrued preclinical trail expenses		0
Percentage of Medicare Part D insurance coverage gap to eligible patients		50.00%
RAVICTI
Summary Of Significant Accounting Policies [Line Items]
Net revenues		8,600,000
Decrease in net loss		$7,900,000
Decrease in earnings per share, basic and diluted		$0.39
Customer Concentration Risk \| Sales Revenue, Goods, Net \| Specialty Distributor
Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration risk by specialty distributor		91.00%	88.00%
United States \| Credit Concentration Risk \| Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration risk by specialty distributor		87.00%	64.00%
International \| Credit Concentration Risk \| Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Percentage of concentration risk by specialty distributor		10.00%	17.00%

Schedule_of_Property_and_Equip

Schedule of Property and Equipment Estimated Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2014
Software
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Minimum \| Computer and office equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Maximum \| Computer and office equipment
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years

Collaboration_Agreement_with_U1

Collaboration Agreement with Ucyclyd Pharma, Inc. - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended	6 Months Ended	12 Months Ended
	31-May-13	Mar. 31, 2012	Jun. 30, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	31-May-13
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Option to purchase rights to BUPHENYL and AMMONUL						$283,000
Purchase option exercise period		90 days
Purchase price for AMMONUL and BUPHENYL		22,000,000
Monthly payments			500,000
Purchase price to retain product rights				32,000,000
Net payment to be received for purchase transaction				11,000,000
Cash paid to Ucyclyd for BUPHENYL product rights				19,000,000
Cash due to Ucyclyd for inventory				2,000,000
Gain from settlement of retention option	31,100,000				31,079,000
Fair value of BUPHENYL	20,400,000						20,400,000
Net payment received from Ucyclyd	11,000,000				10,962,000
Option to purchase rights to BUPHENYL and AMMONUL	300,000				283,000
Purchase agreement with Ucyclyd
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payment under purchase agreement		6,000,000
Purchase agreement with Ucyclyd \| RAVICTI
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Payment under purchase agreement		5,700,000
Purchase agreement with Ucyclyd \| RAVICTI \| Scenario One
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Maximum amount of regulatory milestones, product approval		15,800,000
Regulatory milestones, product approval, description				Regulatory milestones related to approval of GPB in HE
Purchase agreement with Ucyclyd \| RAVICTI \| Scenario Two
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Regulatory milestones, product approval, description				Regulatory milestones approval of GPB in indications other than UCD or HE
Maximum amount of regulatory milestones, approval in other indications		7,300,000
Purchase agreement with Ucyclyd \| RAVICTI \| Scenario Three
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Regulatory milestones, product approval, description				Net sales milestones if GPB is approved for use in indications other than UCD (such as HE) and all annual sales targets are reached
Maximum amount of regulatory milestones, approval in other indications		38,800,000
Purchase agreement with Ucyclyd \| BUPHENYL and AMMONUL
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Option to purchase rights to BUPHENYL and AMMONUL		$300,000

Acquisitions_Additional_Inform

Acquisitions - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended								12 Months Ended		0 Months Ended	7 Months Ended
Acquisitions - Additional Information (Detail) (USD $)	31-May-13	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Jun. 12, 2014	Dec. 31, 2013
Business Acquisition [Line Items]
Net revenue		$30,805,000	$26,201,000	$37,095,000	$19,483,000	$18,627,000	$15,489,000	$7,305,000	$783,000	$113,584,000	$42,204,000
Net payment to be received for purchase transaction										11,000,000
Cash paid to Ucyclyd for BUPHENYL product rights										19,000,000
Cash due to Ucyclyd for inventory										2,000,000
Purchase price to retain product rights		32,000,000								32,000,000
Gain from settlement of retention option	31,100,000										31,079,000
Fair value of BUPHENYL	20,400,000
Net payment received from Ucyclyd	11,000,000										10,962,000
Option to purchase rights to BUPHENYL and AMMONUL	300,000										283,000
Andromeda
Business Acquisition [Line Items]
Acquisition date										12-Jun-14
Contingent liabilities												34,288,000
Issuance of common stock as part of acquisition												312,869
Acquisition-related expenses										1,300,000	600,000
BUPHENYL
Business Acquisition [Line Items]
Acquisition date										31-May-13
Net revenue													11,500,000
Net payment to be received for purchase transaction	11,000,000
Cash paid to Ucyclyd for BUPHENYL product rights	19,000,000
Cash due to Ucyclyd for inventory	2,038,000
Purchase price to retain product rights	32,000,000
Expected useful life of acquired product rights	10 years									8 years
Gain from settlement of retention option	31,079,000							31,100,000
Fair value of BUPHENYL	20,400,000
Net payment received from Ucyclyd	10,962,000
Option to purchase rights to BUPHENYL and AMMONUL	$283,000

Consideration_for_Acquisition_

Consideration for Acquisition Transferred (Detail) (USD $)	12 Months Ended	0 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 12, 2014
Business Acquisition, Contingent Consideration [Line Items]
Cash paid	$14,345
Measurement Period Adjustments
Business Acquisition, Contingent Consideration [Line Items]
Cash paid		14,345
Fair value of Company's common stock issued (312,869 shares)		7,778
Total fair value of consideration transferred		22,123
Andromeda
Business Acquisition, Contingent Consideration [Line Items]
Cash paid			14,345
Fair value of Company's common stock issued (312,869 shares)			7,778
Acquisition-related contingent consideration			68,961
Total fair value of consideration transferred			$91,084

Consideration_for_Acquisition_1

Consideration for Acquisition Transferred (Parenthetical) (Detail)	0 Months Ended
	Jun. 12, 2014	Sep. 30, 2014
Andromeda
Business Acquisition, Contingent Consideration [Line Items]
Fair value of Company's common stock issued, shares	312,869
Measurement Period Adjustments
Business Acquisition, Contingent Consideration [Line Items]
Fair value of Company's common stock issued, shares		312,869

Allocation_of_Purchase_Price_t

Allocation of Purchase Price to the Fair Values of Assets Acquired and Liabilities Assumed (Detail) (USD $)	Jun. 12, 2014	Sep. 30, 2014
In Thousands, unless otherwise specified	Jun. 12, 2014	Sep. 30, 2014
Andromeda
Assets acquired
IPR&D	$135,712
Cash and cash equivalents	306
Prepaid expenses	95
Property and equipment, net	22
Other assets	578
Liabilities assumed
Current liabilities	-9,079
Deferred tax liability	-6,051
Acquisition related contingent liability	-34,288
Total identifiable net assets (liabilities)	87,295
Goodwill	3,789
Total consideration transferred	91,084
Measurement Period Adjustments
Assets acquired
Cash and cash equivalents		306
Prepaid expenses		95
Property and equipment, net		22
Other assets		578
Liabilities assumed
Current liabilities		-9,079
Total identifiable net assets (liabilities)		-8,078
Goodwill		30,201
Total consideration transferred		$22,123

Schedule_of_Purchase_Price_All

Schedule of Purchase Price Allocation (Detail) (USD $)	Dec. 31, 2014	31-May-13
In Thousands, unless otherwise specified	Dec. 31, 2014	31-May-13
Business Acquisition [Line Items]
Purchase price and fair values of assets acquired, total		$20,400
BUPHENYL
Business Acquisition [Line Items]
Inventories		3,900
Intangible Asset - BUPHENYL Product rights	16,500	16,500
Purchase price and fair values of assets acquired, total		$20,400

Total_Gain_from_BUPHENYL_Acqui

Total Gain from BUPHENYL Acquisition (Detail) (USD $)	0 Months Ended	12 Months Ended		3 Months Ended
Total Gain from BUPHENYL Acquisition (Detail) (USD $)	31-May-13	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2013
Business Acquisition [Line Items]
Amount due to Ucyclyd for BUPHENYL product rights		($19,000,000)
Amount due to Ucyclyd for inventory		-2,000,000
Net payment received from Ucyclyd	11,000,000		10,962,000
Option to purchase the rights to BUPHENYL and AMMONUL	-300,000		-283,000
Fair value of BUPHENYL	20,400,000
Gain from settlement of retention option	31,100,000		31,079,000
BUPHENYL
Business Acquisition [Line Items]
Ucyclyd's retention option amount	32,000,000
Amount due to Ucyclyd for BUPHENYL product rights	-19,000,000
Amount due to Ucyclyd for inventory	-2,038,000
Net payment received from Ucyclyd	10,962,000
Option to purchase the rights to BUPHENYL and AMMONUL	-283,000
Fair value of BUPHENYL	20,400,000
Gain from settlement of retention option	$31,079,000			$31,100,000

Consolidated_Pro_Forma_Informa

Consolidated Pro Forma Information (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Combinations [Abstract]
Net revenues	$113,584	$52,900	$21,501
Net income (loss)	$20,390	($12,199)	($29,201)
Net income (loss) per common share
Basic	$0.99	($0.62)	($4.02)
Diluted	$0.93	($0.62)	($4.02)

Schedule_of_Investments_by_Con

Schedule of Investments by Contractual Maturity (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Contractual Maturity Year One	$34,512	$28,075
Contractual Maturity Year Two	9,251	15,805
Contractual Maturity, Total Book Value	43,763	43,880
Unrealized Loss	-50	-55
Aggregate Fair Value	43,713	43,825
Corporate notes
Schedule of Available-for-sale Securities [Line Items]
Contractual Maturity Year One	12,613	6,047
Contractual Maturity Year Two	3,011	12,960
Contractual Maturity, Total Book Value	15,624	19,007
Unrealized Loss	-12	-24
Aggregate Fair Value	15,612	18,983
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Contractual Maturity Year One	18,405	10,525
Contractual Maturity Year Two	6,240	2,845
Contractual Maturity, Total Book Value	24,645	13,370
Unrealized Loss	-35	-27
Aggregate Fair Value	24,610	13,343
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Contractual Maturity Year One	3,494	3,492
Contractual Maturity, Total Book Value	3,494	3,492
Unrealized Loss	-3	-1
Aggregate Fair Value	3,491	3,491
U.S. Government agency securities
Schedule of Available-for-sale Securities [Line Items]
Contractual Maturity Year One		8,011
Contractual Maturity, Total Book Value		8,011
Unrealized Loss		-3
Aggregate Fair Value		$8,008

Investments_Additional_Informa

Investments - Additional Information (Detail) (USD $)	12 Months Ended
Investments - Additional Information (Detail) (USD $)	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Other-than-temporary impairments	$0

Schedule_of_Unrealized_Losses_

Schedule of Unrealized Losses and Related Fair Value of Investments with Unrealized Losses (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months to Maturity, Aggregate Fair Value	$34,487	$28,045
Less Than 12 Months to Maturity, Unrealized Losses	-24	-30
12 Months or More to Maturity, Aggregate Fair Value	9,226	15,780
12 Months or More to Maturity, Unrealized Losses	-26	-25
Aggregate Fair Value, Total	43,713	43,825
Unrealized Losses, Total	-50	-55
Corporate notes
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months to Maturity, Aggregate Fair Value	12,610	6,039
Less Than 12 Months to Maturity, Unrealized Losses	-2	-8
12 Months or More to Maturity, Aggregate Fair Value	3,002	12,944
12 Months or More to Maturity, Unrealized Losses	-10	-16
Aggregate Fair Value, Total	15,612	18,983
Unrealized Losses, Total	-12	-24
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months to Maturity, Aggregate Fair Value	18,386	10,507
Less Than 12 Months to Maturity, Unrealized Losses	-19	-18
12 Months or More to Maturity, Aggregate Fair Value	6,224	2,836
12 Months or More to Maturity, Unrealized Losses	-16	-9
Aggregate Fair Value, Total	24,610	13,343
Unrealized Losses, Total	-35	-27
U.S. Government agency securities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months to Maturity, Aggregate Fair Value		8,008
Less Than 12 Months to Maturity, Unrealized Losses		-3
Aggregate Fair Value, Total		8,008
Unrealized Losses, Total		-3
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months to Maturity, Aggregate Fair Value	3,491	3,491
Less Than 12 Months to Maturity, Unrealized Losses	-3	-1
Aggregate Fair Value, Total	3,491	3,491
Unrealized Losses, Total	($3)	($1)

Hierarchy_for_Assets_and_Liabi

Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	$39,252	$38,986
Fair value of available-for-sale securities	43,713	43,825
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	720	480
Fair value of available-for-sale securities	24,610	13,343
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	3,491	3,491
U.S. Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities		8,008
Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	15,612	18,983
Available-for-sale securities, Short-term
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	34,487	28,045
Available-for-sale securities, Short-term \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	18,386	10,507
Available-for-sale securities, Short-term \| Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	3,491	3,491
Available-for-sale securities, Short-term \| U.S. Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities		8,008
Available-for-sale securities, Short-term \| Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	12,610	6,039
Available-for-sale securities, Long-term
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	9,226	15,780
Available-for-sale securities, Long-term \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	6,224	2,836
Available-for-sale securities, Long-term \| Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	3,002	12,944
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	38,532	38,506
Quoted Prices in Active Markets for Identical Items (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	38,532	38,506
Quoted Prices in Active Markets for Identical Items (Level 1) \| Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	38,532	38,506
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	720	480
Fair value of available-for-sale securities	43,713	43,825
Significant Other Observable Inputs (Level 2) \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash equivalents	720	480
Significant Other Observable Inputs (Level 2) \| Available-for-sale securities, Short-term
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	34,487	28,045
Significant Other Observable Inputs (Level 2) \| Available-for-sale securities, Short-term \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	18,386	10,507
Significant Other Observable Inputs (Level 2) \| Available-for-sale securities, Short-term \| Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	3,491	3,491
Significant Other Observable Inputs (Level 2) \| Available-for-sale securities, Short-term \| U.S. Government agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities		8,008
Significant Other Observable Inputs (Level 2) \| Available-for-sale securities, Short-term \| Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	12,610	6,039
Significant Other Observable Inputs (Level 2) \| Available-for-sale securities, Long-term
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	9,226	15,780
Significant Other Observable Inputs (Level 2) \| Available-for-sale securities, Long-term \| Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	6,224	2,836
Significant Other Observable Inputs (Level 2) \| Available-for-sale securities, Long-term \| Corporate notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of available-for-sale securities	$3,002	$12,944

Carrying_Value_and_Estimated_F

Carrying Value and Estimated Fair Value of Company's Notes Payable and Term Loans (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Term Loans \| Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	$16,124
Term Loans \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	16,746
April and September 2012 Notes \| Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total		8,273
April and September 2012 Notes \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total		$8,860

Components_of_Inventories_Deta

Components of Inventories (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Raw Materials	$1,787	$697
Work-in-process	543
Finished goods	2,291	2,816
Total	$4,621	$3,513

Inventories_Additional_Informa

Inventories - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Inventory reserves	$0.30	$0

Intangible_Assets_and_Goodwill2

Intangible Assets and Goodwill - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended		0 Months Ended
	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	31-May-13	Jun. 12, 2014
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible asset		$4,626,000	$3,058,000
Goodwill acquired		30,200,000
Impairment loss	30,200,000
BUPHENYL
Finite-Lived Intangible Assets [Line Items]
Intangible asset acquired		16,500,000		16,500,000
Estimated useful life of intangible assets		10 years
Remaining weighted average useful life		8 years		10 years
Andromeda
Finite-Lived Intangible Assets [Line Items]
Intangible asset acquired					135,712,000
Impairment loss		30,200,000
Fair value of goodwill		0
Andromeda \| Implied
Finite-Lived Intangible Assets [Line Items]
Fair value of goodwill		$0

Schedule_of_Expected_Amortizat

Schedule of Expected Amortization Expense (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
2015	$6,495
2016	1,655
2017	1,515
2018	1,477
2019	$1,441

Components_of_Property_and_Equ

Components of Property and Equipment (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$1,756	$1,200
Less: Accumulated depreciation	-640	-264
Total property and equipment, net	1,116	936
Computers and Software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,202	563
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	320	320
Office Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	53	53
Capital work in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$181	$264

Property_and_Equipment_Additio

Property and Equipment - Additional Information (Detail) (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	$496	$198	$15

Components_of_Accrued_Liabilit

Components of Accrued Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Payables and Accruals [Abstract]
Clinical trial expenses	$2,399	$246
Payroll and related expenses	4,134	4,278
Gross to net sales accruals	10,142	5,235
Royalty payable	2,080	1,154
Taxes payable	563	326
Legal expenses payable	410	45
Acquisition related accrual (Note 22)	4,615
Other	1,166	903
Accrued liabilities	$25,509	$12,187

Notes_Payable_Additional_Infor

Notes Payable - Additional Information (Detail) (April 2011 Convertible Notes Payable, USD $)	0 Months Ended	1 Months Ended
	Jul. 31, 2012	Apr. 30, 2011	Jul. 31, 2012	31-May-11
April 2011 Convertible Notes Payable
Debt Instrument [Line Items]
Aggregate principal amount of notes issued		$17,500,000		$8,285
Aggregate principal amount that may be issued, maximum		35,000,000
Stated interest rate on notes		6.00%
Portion of principal amount outstanding for holders having early maturity date		66.00%
Minimum amount of proceeds from preferred stock		30,000,000
Principal and accrued interest converted upon closing of IPO	18,900,000		18,900,000
Number of shares issued upon conversion of notes	1,888,054
Carrying value and accrued interest	$18,400,000		$18,400,000

Notes_Payable_Additional_Infor1

Notes Payable - Additional Information 1 (Detail) (USD $)	0 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended
Notes Payable - Additional Information 1 (Detail) (USD $)	Jul. 31, 2012	Oct. 31, 2011	Dec. 31, 2012	Feb. 29, 2012	Dec. 31, 2014	Nov. 30, 2011
October 2011 Convertible Notes Payable
Debt Instrument [Line Items]
Aggregate principal amount of notes issued		$7,500,000		$7,500,000		$3,551
Aggregate principal amount that may be issued, maximum		15,000,000
Stated interest rate on notes		6.00%
Portion of principal amount outstanding for holders having early maturity date		66.00%
Minimum amount of proceeds from preferred stock		40,000,000
Principal and accrued interest converted upon closing of IPO	15,600,000
Number of shares issued upon conversion of notes	1,556,816
Carrying value and accrued interest	14,900,000
Amortization of debt discount			900,000
Carrying value of notes			0
Beneficial conversion features					0
October 2011 Call Option Liability
Debt Instrument [Line Items]
Aggregate principal amount in event that none of subsequent closing notes issued					7,500,000
Aggregate principal amount in event that all or portion of subsequent closing notes issued					7,500,000
Amortization of debt discount		800,000
Other Income (Expense)				$700,000

Notes_Payable_Additional_Infor2

Notes Payable - Additional Information 2 (Detail) (USD $)	12 Months Ended	0 Months Ended	1 Months Ended		12 Months Ended
Notes Payable - Additional Information 2 (Detail) (USD $)	Dec. 31, 2014	Jul. 18, 2014	Apr. 30, 2012	Sep. 30, 2012	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Loss on extinguishment of debt	$600,000
Silicon Valley Bank
Debt Instrument [Line Items]
Final payment due as a percentage of principal loan amount	6.75%
Pre-payment of term loans		5,800,000
Repayment of loans, description	The Company is required to pay interest only for the first 18 months of the Term Loans, followed by 30 equal monthly payments of interest and principal.
Interest rate on loans, description	The Loan Agreement provides for an interest rate of 4.0% per year on the Term Loans and the prime rate plus 0.75% per year on the Revolving Loans, with a minimum interest requirement on the Revolving Loans.
Percentage Of Financial Instruments	75.00%
Value Of Financial Instruments	40,000,000
Debt Instrument, Covenant Description	At least the lesser of (i) seventy five percent (75%) of the dollar value of the Company and its Subsidiaries' accounts at all financial institutions or (ii) $40.0 million; provided, however, that the Company's obligation relating to foreign exchange transactions is subject to SVB providing commercially competitive exchange rates.
Silicon Valley Bank \| Term Loans
Debt Instrument [Line Items]
Number of tranches		2
Loan and security agreement, maximum borrowings		16,000,000
Term loans maturity date	30-Jun-18
Silicon Valley Bank \| Revolving Loans
Debt Instrument [Line Items]
Loan and security agreement, maximum borrowings		5,000,000
Drew down from revolving line of credit facility		2,000,000
Term loans maturity date	18-Jul-17
April 2012 Notes Payable
Debt Instrument [Line Items]
Aggregate principal amount of notes issued			10,000,000
Stated interest rate on notes			8.88%
Interest only payment period			9 months
Payment of loan principal and interest			27 months
Period for monthly financials and compliance certificate			30 days
Period for annual audited financial report			180 days
Number of warrants issued			75,974
Exercise price of warrants			$4.08
Final payment due as a percentage of principal loan amount			6.50%
Sale of equity securities or debt, minimum amount for term loan	30,000,000
September 2012 Notes Payable
Debt Instrument [Line Items]
Stated interest rate on notes				8.88%
Interest only payment period				9 months
Payment of loan principal and interest				27 months
Number of warrants issued				8,408
Exercise price of warrants				$5.05
Final payment due as a percentage of principal loan amount				6.50%
Additional borrowing				2,500,000
Percentage in addition to Treasury rate, term loan				8.50%
April 2012 and September 2012 Notes Payable and Term Loans
Debt Instrument [Line Items]
Amortization of debt discount	$800,000				$500,000	$400,000

Future_Minimum_Payments_Under_

Future Minimum Payments Under Loan Agreement (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Less: current portion		($5,652)
Non-current portion	18,124	2,621
Loan Agreement
Debt Instrument [Line Items]
2015	730
2016	6,822
2017	8,786
2018	4,450
Total future minimum payments	20,788
Less: amount representing unamortized interest	-1,709
Less: amount representing debt discount	-955
Total minimum payments	18,124
Less: current portion	0
Non-current portion	$18,124

Warrants_Additional_Informatio

Warrants - Additional Information (Detail) (October 2007 Common Stock Warrants, USD $)	12 Months Ended
	Dec. 31, 2014	Oct. 31, 2007
October 2007 Common Stock Warrants
Class of Warrant or Right [Line Items]
Number of warrants issued		274
Exercise price of warrants	$1,913.05
Expiration date of warrants	Oct-17

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended
	Oct. 14, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 16, 2015	Sep. 22, 2014	Dec. 12, 2013
	Oct. 14, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 16, 2015	Sep. 22, 2014	sqft
Loss Contingencies [Line Items]
Leased space	20,116						352
Initial lease term		6 years
Total base rent	$4,500,000
Lease commencement date		19-Nov-13
Total monthly base rent		100,000
Lease expiration date		2016-12
Rent expense including maintenance fees		800,000	400,000	300,000
Allegation description		CBI filed suit against the Company in Superior Court of the state of Delaware for New Castle County alleging breach of contract and breach of the implied covenant of good faith and fair dealing under the SPA with CBI relating related to the acquisition of Andromeda.
Common Stock [Member]
Loss Contingencies [Line Items]
Number of trading days for valuation of shares		15 days
Andromeda
Loss Contingencies [Line Items]
Estimated budget for trial		10,500,000
Increase in estimated budget for trial		2,250,000
Option to acquire outstanding stock payable		3,500,000
Andromeda \| Subsequent Events
Loss Contingencies [Line Items]
Milestone payment exchange					500,000
Andromeda \| Common Stock [Member]
Loss Contingencies [Line Items]
Consideration paid in shares of common stock		2,500,000
Andromeda \| Common Stock [Member] \| Subsequent Events
Loss Contingencies [Line Items]
Number of trading days for valuation of shares					15 days
Andromeda
Loss Contingencies [Line Items]
Lawsuit filing date		22-Sep-14
File suit for damages relating to acquisition						200,000,000
Estimated budget for trial		10,500,000
Increase in estimated budget for trial		2,250,000
Option to acquire outstanding stock payable		3,500,000
Andromeda \| Subsequent Events
Loss Contingencies [Line Items]
Milestone payment exchange					500,000
Andromeda \| Maximum
Loss Contingencies [Line Items]
Contingent payments based on future revenue		$36,500,000

Future_Minimum_Lease_Payments_

Future Minimum Lease Payments (Detail) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
2015	$797
2016	820
2017	821
2018	845
2019	766
Total	$4,049

Preferred_Stock_Additional_Inf

Preferred Stock - Additional Information (Detail) (USD $)	0 Months Ended
In Millions, except Share data, unless otherwise specified	Jul. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Jul. 31, 2012
Temporary Equity [Line Items]
Total value of preferred stock converted	$58.30
Preferred stock, authorized	10,000,000	10,000,000	10,000,000	10,000,000
Preferred stock, par value	$0.00	$0.00	$0.00	$0.00
Preferred stock, outstanding		0	0
Series C-1 Convertible Preferred Stock
Temporary Equity [Line Items]
Issuance of common stock for converted preferred stock	1,912,598			1,912,598
Series C-2 Convertible Preferred Stock
Temporary Equity [Line Items]
Issuance of common stock for converted preferred stock	4,663,039			4,663,039

Common_Stock_Additional_Inform

Common Stock - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended		0 Months Ended
Common Stock - Additional Information (Detail) (USD $)	Jul. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Mar. 13, 2013	Dec. 31, 2014	Aug. 14, 2013
Common Stock [Line Items]
Offering price per share	$10
Additional shares issued for over-allotment	750,000
Net proceeds from initial public offering			$53,475,000
Underwriting discounts and commissions		4,116,000	4,025,000
Total value of preferred stock converted	58,300,000
Common stock, authorized	100,000,000	100,000,000			100,000,000
Common stock, par value	$0.00	$0.00			$0.00
Votes per common stock	1
Net proceeds from public offering		64,488,000
Aggregate offering price						150,000,000
Common stock shares sold by selling stockholders						8,727,000
Aggregate offering price under sales agreement						50,000,000
Sales of securities					0
April 2011 Convertible Notes Payable
Common Stock [Line Items]
Principal and accrued interest converted upon closing of IPO	18,900,000
Number of shares issued upon conversion of notes	1,888,054
Carrying value and accrued interest	18,400,000
October 2011 Convertible Notes Payable
Common Stock [Line Items]
Principal and accrued interest converted upon closing of IPO	15,600,000
Number of shares issued upon conversion of notes	1,556,816
Carrying value and accrued interest	14,900,000
Series C-1 Convertible Preferred Stock
Common Stock [Line Items]
Issuance of common stock for converted preferred stock	1,912,598
Series C-2 Convertible Preferred Stock
Common Stock [Line Items]
Issuance of common stock for converted preferred stock	4,663,039
April 2011 Common Stock Warrants Liability
Common Stock [Line Items]
Shares issued for conversion of warrants upon closing of IPO	322,599
October 2011 Preferred Stock Warrants Liability
Common Stock [Line Items]
Shares issued for conversion of warrants upon closing of IPO	17,762
April 2011 common stock warrants and October 2011 preferred stock warrants
Common Stock [Line Items]
Fair value of warrants	3,900,000
Initial Public Offering
Common Stock [Line Items]
Common stock, shares issued	5,000,000
Net proceeds from initial public offering	51,300,000
Underwriting discounts and commissions	4,025,000
Other offering expenses	2,200,000
Follow-on offering
Common Stock [Line Items]
Common stock, shares issued				2,875,000
Offering price per share				$20.75
Additional shares issued for over-allotment				431,250
Underwriting discounts and commissions				4,116,000
Other offering expenses				800,000
Net proceeds from public offering				$63,700,000

Common_Stock_Reserved_for_Futu

Common Stock Reserved for Future Issuances (Detail)	Dec. 31, 2014
Common Stock [Line Items]
Common stock reserved for future issuance	3,894,150
Stock options \| 2012 Plan
Common Stock [Line Items]
Common stock reserved for future issuance	688,842
Stock Option Exercises \| 2006 and 2012 Plan
Common Stock [Line Items]
Common stock reserved for future issuance	3,068,741
Restricted and Performance Stock Units Vesting \| 2012 Plan
Common Stock [Line Items]
Common stock reserved for future issuance	136,293
Conversion of Common Stock Warrants \| October 2007 Common Stock Warrants
Common Stock [Line Items]
Common stock reserved for future issuance	274

Stock_Option_Plan_Additional_I

Stock Option Plan - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
Stock Option Plan - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2006
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Closing price of common stock	$24
Weighted-average grant date fair value of options granted		$25.99	$22.90	$6.76
Stock-based compensation		$7,638,000	$4,321,000	$993,000
Unrecognized compensation cost	17,000,000	17,000,000
Period of recognition for unrecognized compensation cost		2 years 6 months
Inventories
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation capitalized into inventories		100,000	100,000
2006 Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Shares reserved for issuance					457
Term of option					10 years
Vesting term					5 years
Aggregate intrinsic value of options exercised		4,100,000
Number of options vested and expected to vest	1,328,822	1,328,822
Options vested and expected to vest, intrinsic value	27,400,000	27,400,000
Options vested and expected to vest, weighted average exercise price	$3.59	$3.59
Options vested and expected to vest, weighted average remaining life		5 years 6 months
2006 Plan \| Minimum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Minimum exercise price as a percentage of fair market value					100.00%
Minimum vesting percentage per year					20.00%
2006 Plan \| Persons Possessing 10% or More of Combined Voting Power
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Term of option					5 years
2006 Plan \| Persons Possessing 10% or More of Combined Voting Power \| Minimum
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Minimum exercise price as a percentage of fair market value					110.00%
Percentage of voting rights held by individual causing change in exercise price					10.00%
2012 Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Shares reserved for issuance	688,842	688,842	576,760
Aggregate intrinsic value of options exercised		800,000
Number of options vested and expected to vest	1,646,570	1,646,570
Options vested and expected to vest, intrinsic value	$3,600,000	$3,600,000
Options vested and expected to vest, weighted average exercise price	$23.02	$23.02
Options vested and expected to vest, weighted average remaining life		8 years 8 months 12 days
Stock options granted		806,919	1,067,315	720,580
2012 Plan \| Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Restricted stock units, Granted		122,155	21,000	0
Stock units outstanding under plan	127,305	127,305	18,000
2012 Plan \| Performance stock units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Restricted stock units, Granted		8,988
Stock units outstanding under plan	8,988	8,988	0	0

Schedule_of_Option_Activity_De

Schedule of Option Activity (Detail) (USD $)	12 Months Ended
Schedule of Option Activity (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
2006 Plan
Number of Shares Available for Grant
Options exercised	0
Options re-allocated	-14,413
Options and awards cancelled	14,413
Number of Shares Underlying Outstanding Options
Beginning Balance	1,538,197
Options exercised	-190,263
Options and awards cancelled	-14,413
Ending Balance	1,333,521
Weighted-Average Exercise Price Per Share
Beginning Balance	$3.64
Options exercised	$3.73
Options and awards cancelled	$6.78
Ending Balance	$3.60
2012 Plan
Number of Shares Available for Grant
Beginning Balance	576,760
Additional shares authorized	805,485
Options and awards granted	-938,062
Options re-allocated	14,413
Options and awards cancelled	230,246
Ending Balance	688,842	576,760
Number of Shares Underlying Outstanding Options
Beginning Balance	1,252,433
Options and awards granted	806,919	1,067,315	720,580
Options exercised	-101,736
Options and awards cancelled	-222,396
Ending Balance	1,735,220	1,252,433
Weighted-Average Exercise Price Per Share
Beginning Balance	$20.75
Options and awards granted	$25.99
Options exercised	$18.42
Options and awards cancelled	$22.66
Ending Balance	$23.08	$20.75
2012 Plan \| Restricted Stock
Number of Shares Underlying Outstanding Options
Beginning Balance	18,000
Options and awards granted	122,155	21,000	0
Awards released	-5,000
Options and awards cancelled	-7,850
Ending Balance	127,305	18,000
Options Vested and Exercisable
Beginning Balance	$19.39
Options and awards granted	$26.68
Awards released	$20.13
Options and awards cancelled	$26.74
Ending Balance	$25.90	$19.39
2012 Plan \| Performance stock units
Number of Shares Underlying Outstanding Options
Beginning Balance	0
Options and awards granted	8,988
Ending Balance	8,988		0
Options Vested and Exercisable
Options and awards granted	$25.08
Ending Balance	$25.08

Aggregate_Options_Outstanding_

Aggregate Options Outstanding and Vested and Exercisable by Exercise Price (Detail) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014
2006 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	1,333,521
Options Outstanding, Aggregate Intrinsic Value	$27,493
Options Outstanding, Weighted Average Remaining Life (in Years)	5 years 6 months
Options Vested and Exercisable, Options Number Outstanding	1,182,263
Options Vested and Exercisable, Aggregate Intrinsic Value	24,892
2012 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	1,735,220
Options Outstanding, Aggregate Intrinsic Value	3,765
Options Outstanding, Weighted Average Remaining Life (in Years)	8 years 8 months 12 days
Options Vested and Exercisable, Options Number Outstanding	450,062
Options Vested and Exercisable, Aggregate Intrinsic Value	1,660
Exercise Price 1 \| 2006 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$1.28
Options Outstanding, Number Outstanding	735,773
Options Outstanding, Aggregate Intrinsic Value	16,717
Options Outstanding, Weighted Average Remaining Life (in Years)	4 years 6 months
Options Vested and Exercisable, Options Number Outstanding	735,773
Options Vested and Exercisable, Aggregate Intrinsic Value	16,717
Options Vested and Exercisable, Exercise Price	$1.28
Exercise Price 1 \| 2012 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	242,962
Options Outstanding, Aggregate Intrinsic Value	2,799
Options Outstanding, Weighted Average Remaining Life (in Years)	7 years 10 months 24 days
Options Vested and Exercisable, Options Number Outstanding	118,837
Options Vested and Exercisable, Aggregate Intrinsic Value	1,415
Exercise Price 1 \| 2012 Plan \| Minimum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$10.32
Options Vested and Exercisable, Exercise Price	$10.32
Exercise Price 1 \| 2012 Plan \| Maximum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$18.24
Options Vested and Exercisable, Exercise Price	$18.24
Exercise Price 2 \| 2006 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$4.08
Options Outstanding, Number Outstanding	252,403
Options Outstanding, Aggregate Intrinsic Value	5,028
Options Outstanding, Weighted Average Remaining Life (in Years)	6 years 3 months 18 days
Options Vested and Exercisable, Options Number Outstanding	228,490
Options Vested and Exercisable, Aggregate Intrinsic Value	4,552
Options Vested and Exercisable, Exercise Price	$4.08
Exercise Price 2 \| 2012 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	200,170
Options Outstanding, Aggregate Intrinsic Value	746
Options Outstanding, Weighted Average Remaining Life (in Years)	9 years
Options Vested and Exercisable, Options Number Outstanding	36,504
Options Vested and Exercisable, Aggregate Intrinsic Value	162
Exercise Price 2 \| 2012 Plan \| Minimum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$19.39
Options Vested and Exercisable, Exercise Price	$19.39
Exercise Price 2 \| 2012 Plan \| Maximum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$21.05
Options Vested and Exercisable, Exercise Price	$21.05
Exercise Price 3 \| 2006 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$7.31
Options Outstanding, Number Outstanding	344,405
Options Outstanding, Aggregate Intrinsic Value	5,748
Options Outstanding, Weighted Average Remaining Life (in Years)	7 years 3 months 18 days
Options Vested and Exercisable, Options Number Outstanding	217,060
Options Vested and Exercisable, Aggregate Intrinsic Value	3,623
Options Vested and Exercisable, Exercise Price	$7.31
Exercise Price 3 \| 2012 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	128,450
Options Outstanding, Aggregate Intrinsic Value	220
Options Outstanding, Weighted Average Remaining Life (in Years)	8 years 8 months 12 days
Options Vested and Exercisable, Options Number Outstanding	41,514
Options Vested and Exercisable, Aggregate Intrinsic Value	$83
Exercise Price 3 \| 2012 Plan \| Minimum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$21.45
Options Vested and Exercisable, Exercise Price	$21.45
Exercise Price 3 \| 2012 Plan \| Maximum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$24.38
Options Vested and Exercisable, Exercise Price	$24.38
Exercise Price 4 \| 2006 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$327.95
Options Outstanding, Number Outstanding	940
Options Outstanding, Weighted Average Remaining Life (in Years)	2 years 6 months
Options Vested and Exercisable, Options Number Outstanding	940
Options Vested and Exercisable, Exercise Price	$327.95
Exercise Price 4 \| 2012 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	1,095,725
Options Outstanding, Weighted Average Remaining Life (in Years)	8 years 9 months 18 days
Options Vested and Exercisable, Options Number Outstanding	253,207
Exercise Price 4 \| 2012 Plan \| Minimum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$24.46
Options Vested and Exercisable, Exercise Price	$24.46
Exercise Price 4 \| 2012 Plan \| Maximum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$26.74
Options Vested and Exercisable, Exercise Price	$26.74
Exercise Price 5 \| 2012 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	42,313
Options Outstanding, Weighted Average Remaining Life (in Years)	9 years 3 months 18 days
Exercise Price 5 \| 2012 Plan \| Minimum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$26.97
Options Vested and Exercisable, Exercise Price	$26.97
Exercise Price 5 \| 2012 Plan \| Maximum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$28.08
Options Vested and Exercisable, Exercise Price	$28.08
Exercise Price 6 \| 2012 Plan
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	25,600
Options Outstanding, Weighted Average Remaining Life (in Years)	9 years 3 months 18 days
Exercise Price 6 \| 2012 Plan \| Minimum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$29.27
Options Vested and Exercisable, Exercise Price	$29.27
Exercise Price 6 \| 2012 Plan \| Maximum
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Exercise Price	$31
Options Vested and Exercisable, Exercise Price	$31

WeightedAverage_Assumptions_fo

Weighted-Average Assumptions for Fair Value of Stock Options (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected volatility	62.76%	58.00%	65.00%
Risk-free interest rate	1.90%	1.14%	1.05%
Dividend yield	0.00%	0.00%	0.00%
Expected term (in years)	6 years	5 years 11 months 16 days	6 years

Allocation_of_StockBased_Compe

Allocation of Stock-Based Compensation Expense (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses related to employees	$7,638	$4,321	$993
Cost of sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses related to employees	70	27
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses related to employees	1,384	585	374
Selling general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses related to employees	$6,184	$3,709	$619

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
Income Taxes - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Tax Credit Carryforward [Line Items]
Income (loss) before income taxes	($5,952,000)	$16,676,000	($32,263,000)
Statutory federal income tax rate	35.00%	35.00%	34.00%
Increase (decrease) in deferred tax asset valuation allowance	26,100,000
Excess tax deductions from stock-based compensation expense	4,000,000
Minimum percentage of stock for change of ownership	50.00%
Term of acquisition/sales for change of ownership	3 years
Percentage of total equity value of acquiree or seller for change in ownership	5.00%
Annual limitation on ownership change	50,000,000
Interest or penalties accrued	0
Other non-current assets
Tax Credit Carryforward [Line Items]
Non-current deferred income tax asset	1,400,000	200,000
Prepaid expenses and other current assets
Tax Credit Carryforward [Line Items]
Current deferred income tax asset		100,000
United States
Tax Credit Carryforward [Line Items]
Income (loss) before income taxes	30,000,000	16,700,000	-32,300,000
Net operating loss carryforwards	36,400,000
Operating loss expirations	Begin to expire in 2031
Tax credit carryforward	22,600,000
United States \| Research and development tax credit carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward	22,600,000
Outside United States
Tax Credit Carryforward [Line Items]
Income (loss) before income taxes	-36,000,000
California
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	107,800,000
Operating loss expirations	Begin to expire in 2028
Tax credit carryforward	700,000
Israel Tax Authority
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	67,300,000
Operating loss expirations	Do not expire
Minimum \| United States
Tax Credit Carryforward [Line Items]
Tax credit carryforward expiration	2027
Federal Orphan Drug Credit \| United States \| Research and development tax credit carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforward	$21,100,000

Components_of_Income_Tax_Expen

Components of Income Tax Expense (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current income tax expense:
Federal	$736
State	703	326
Total current income tax expense	1,439	326
Deferred income tax benefit:
State	-1,136	-277
Total deferred income tax benefit	-1,136	-277
Total income tax expense	$303	$49

Reconciliation_of_Income_Tax_E

Reconciliation of Income Tax Expense (Detail)	12 Months Ended
Reconciliation of Income Tax Expense (Detail)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Statutory rate	35.00%	35.00%	34.00%
State tax	0.60%	5.50%	5.40%
Tax credits	57.50%	-5.00%	0.70%
Stock options	-28.00%	0.20%	-0.70%
Valuation allowance	-81.80%	-29.60%	-37.10%
Impact of Andromeda acquisition	12.60%
Change in federal tax rate		-6.00%
Other	-1.00%	0.20%	-2.30%
Effective Income Tax Rate, Continuing Operations, Total	-5.10%	0.30%	0.00%

Components_of_Deferred_Income_

Components of Deferred Income Tax Assets (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred income tax assets
Fixed assets, capitalized intangibles and other assets	$6,030	$5,294
Net operating loss	35,164	31,842
Tax credits	23,024	18,480
Stock-based compensation expense	1,660	1,133
Accrued expenses and reserves	3,405	1,502
Capitalized research and development expenses	3,237
Tax basis in investments	12,624
Other	381	25
Total	85,525	58,276
Valuation allowance	-84,113	-58,000
Net deferred income tax assets	$1,412	$276

Reconciliation_of_Beginning_an

Reconciliation of Beginning and Ending Balances of Unrecognized Income Tax Benefits (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Balance at the beginning of the year	$6,269	$5,723	$5,357
Changes based on prior period tax positions	-2,325		-228
Changes based on current period tax positions	223	546	594
Balance at the end of the year	$4,167	$6,269	$5,723

Defined_Contribution_Plan_Addi

Defined Contribution Plan - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Amount of contribution to Plan	$300,000	$200,000	$0

Recovered_Sheet1

Net Income (Loss) Per Share of Common Stock (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net income (loss) per share Numerator:
Net income (loss) attributable to common stockholders	$7,096	($32,793)	$18,183	$1,259	$468	$112	$25,022	($8,975)	($6,255)	$16,627	($32,263)
Denominator:
Basic									20,470,025	19,415,822	7,256,537
Dilutive effect of stock-options and awards										1,315,091
Diluted									20,470,025	20,730,913	7,256,537
Net income (loss) per share:
Basic	$0.34	($1.59)	$0.89	$0.06	$0.02	$0.01	$1.25	($0.52)	($0.31)	$0.86	($4.45)
Diluted	$0.32	($1.59)	$0.84	$0.06	$0.02	$0.01	$1.17	($0.52)	($0.31)	$0.80	($4.45)

Antidilutive_Securities_Exclud

Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from the computation of diluted net loss per share	3,069,015	1,027,879	2,013,410
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from the computation of diluted net loss per share	3,068,741	1,027,605	1,928,754
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from the computation of diluted net loss per share	274	274	84,656

Related_Party_Transaction_Addi

Related Party Transaction - Additional Information (Detail) (Swedish Orphan Biovitrum AB, USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Swedish Orphan Biovitrum AB
Related Party Transaction [Line Items]
Sales recognized	$5.10	$2.20
Accounts receivable from SOBI	$1.50	$0.70

Net_Product_Revenue_for_Ravict

Net Product Revenue for Ravicti and Buphenyl (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Revenue from External Customer [Line Items]
Revenue	$113,584	$42,204
RAVICTI
Revenue from External Customer [Line Items]
Revenue	95,400	31,236
BUPHENYL
Revenue from External Customer [Line Items]
Revenue	18,584	11,468
Co-payment assistance
Revenue from External Customer [Line Items]
Revenue	($400)	($500)

Net_Product_Revenue_for_Ravict1

Net Product Revenue for Ravicti and Buphenyl by Geographic Region (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenue	$113,584	$42,204
United States
Segment Reporting Information [Line Items]
Revenue	103,303	37,102
Canada
Segment Reporting Information [Line Items]
Revenue	3,723	2,208
Rest of the world
Segment Reporting Information [Line Items]
Revenue	$6,558	$2,894

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail)	12 Months Ended	3 Months Ended	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2014	Feb. 16, 2015	Feb. 16, 2015	Feb. 16, 2015
	Andromeda	Scenario, Forecast [Member]	Common Stock [Member]	Common Stock [Member]	Evotec	Subsequent Events	Subsequent Events	Subsequent Events
	USD ($)	Andromeda		Andromeda	Maximum	Andromeda	Common Stock [Member]	Evotec
		USD ($)		USD ($)	Andromeda	USD ($)	Andromeda	Andromeda
					USD ($)			EUR (€)
Subsequent Event [Line Items]
Estimated budget for clinical trial	$10,500,000
Increase in estimated budget for clinical trial	2,250,000
Option to acquire outstanding stock payable	3,500,000
Contingent payments based on future revenue					36,500,000			3,380,000
Consideration paid in shares of common stock				2,500,000
Option expiration date	30-Sep-15
Number of trading days for valuation of shares			15 days				15 days
Accrued liabilities	4,600,000
Other income		4,100,000
Milestone payment exchange						$500,000

Selected_Unaudited_Quarterly_F

Selected Unaudited Quarterly Financial Information (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Product revenue, net	$30,805	$26,201	$37,095	$19,483	$18,627	$15,489	$7,305	$783	$113,584	$42,204
Costs and expenses	24,078	55,031	20,898	17,784	17,747	15,037	12,986	9,851	117,791	55,621	28,533
Net income (loss) attributable to common stockholders	$7,096	($32,793)	$18,183	$1,259	$468	$112	$25,022	($8,975)	($6,255)	$16,627	($32,263)
Net income (loss) per share attributable to common stockholders - basic	$0.34	($1.59)	$0.89	$0.06	$0.02	$0.01	$1.25	($0.52)	($0.31)	$0.86	($4.45)
Net income (loss) per share attributable to common stockholders - diluted	$0.32	($1.59)	$0.84	$0.06	$0.02	$0.01	$1.17	($0.52)	($0.31)	$0.80	($4.45)

Selected_Unaudited_Quarterly_F1

Selected Unaudited Quarterly Financial Information (Parenthetical) (Detail) (USD $)	0 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended
	31-May-13	Sep. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Schedule Of Quarterly Financial Information [Line Items]
Impairment charge of goodwill		$30,200,000
Gain from settlement of retention option	31,100,000		31,079,000
BUPHENYL
Schedule Of Quarterly Financial Information [Line Items]
Gain from settlement of retention option	$31,079,000			$31,100,000