XenoPort (XNPT) 10-Q 9 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 15, 2014
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'XNPT	'
Entity Registrant Name	'XENOPORT INC	'
Entity Central Index Key	'0001130591	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	61,893,750

BALANCE_SHEETS

BALANCE SHEETS (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$17,818	$20,584
Short-term investments	104,645	38,074
Accounts receivable	1,231	939
Inventories	1,364	1,262
Prepaids and other current assets	3,409	2,826
Total current assets	128,467	63,685
Property and equipment, net	2,353	2,552
Long-term inventories	10,030	10,185
Restricted investments and other assets	2,055	2,119
Total assets	142,905	78,541
Current liabilities:	'	'
Accounts payable	4,480	1,432
Accrued compensation	3,055	2,741
Accrued preclinical and clinical costs	930	824
Other accrued liabilities	6,325	3,938
Deferred revenue	1,134	1,134
Total current liabilities	15,924	10,069
Deferred revenue	11,714	11,997
Other noncurrent liability	2,896	2,782
Commitments and contingencies	'	'
Stockholders' equity:	'	'
Preferred stock, $0.001 par value; 5,000 shares authorized; no shares issued or outstanding	'	'
Common stock, $0.001 par value; 100,000 shares authorized; 61,889 and 47,800 shares issued and outstanding, at March 31, 2014 and December 31, 2013, respectively	62	48
Additional paid-in capital	670,344	591,128
Accumulated other comprehensive loss	-4	'
Accumulated deficit	-558,031	-537,483
Total stockholders' equity	112,371	53,693
Total liabilities and stockholders' equity	$142,905	$78,541

BALANCE_SHEETS_Parenthetical

BALANCE SHEETS (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Per Share data, unless otherwise specified
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares issued	'	'
Preferred stock, shares outstanding	'	'
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	100,000	100,000
Common stock, shares issued	61,889	47,800
Common stock, shares outstanding	61,889	47,800

STATEMENTS_OF_COMPREHENSIVE_LO

STATEMENTS OF COMPREHENSIVE LOSS (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Revenues:	'	'
Product sales, net	$2,957	'
Collaboration revenue	283	379
Royalty revenue	135	80
Total revenues	3,375	459
Operating expenses:	'	'
Cost of product sales	430	'
Research and development	4,657	13,353
Selling, general and administrative	18,771	10,735
Total operating expenses	23,858	24,088
Loss from operations	-20,483	-23,629
Interest income	49	81
Interest expense	-114	'
Net loss	-20,548	-23,548
Other comprehensive loss:	'	'
Unrealized gains (losses) on available-for-sale securities	-4	-19
Comprehensive loss	($20,552)	($23,567)
Basic and diluted net loss per share	($0.36)	($0.50)
Shares used to compute basic and diluted net loss per share	56,887	47,249

STATEMENTS_OF_CASH_FLOWS

STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating activities	'	'
Net loss	($20,548)	($23,548)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation and amortization	199	313
Accretion of investment discounts and amortization of investment premiums, net	216	314
Stock-based compensation expense	2,684	3,344
Changes in assets and liabilities:	'	'
Accounts receivable	-292	'
Prepaids and other current and noncurrent assets	-519	-2,501
Inventories	53	'
Accounts payable	3,048	1,611
Accrued compensation	314	-1,995
Accrued restructuring charges	'	-445
Accrued preclinical and clinical costs	106	485
Other accrued liabilities, current and noncurrent	2,501	1,002
Deferred revenue, current and noncurrent	-283	-379
Net cash used in operating activities	-12,521	-21,799
Investing activities	'	'
Purchases of investments	-90,148	-34,242
Proceeds from maturities of investments	23,357	42,662
Purchases of property and equipment	'	-168
Net cash provided by (used in) investing activities	-66,791	8,252
Financing activities	'	'
Net cash proceeds provided by (used in) issuance of common stock and exercise of stock options	76,546	-1,576
Net cash provided by (used in) financing activities	76,546	-1,576
Net decrease in cash and cash equivalents	-2,766	-15,123
Cash and cash equivalents at beginning of period	20,584	36,134
Cash and cash equivalents at end of period	$17,818	$21,011

Organization_and_Summary_of_Si

Organization and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
Organization and Summary of Significant Accounting Policies	'
	1. Organization and Summary of Significant Accounting Policies
	Nature of Operations
	XenoPort, Inc., or the Company, was incorporated in the state of Delaware on May 19, 1999. The Company is a biopharmaceutical company focused on developing and commercializing a portfolio of internally discovered product candidates for the potential treatment of neurological and other disorders. The Company is currently commercializing HORIZANT® (gabapentin enacarbil) Extended-Release Tablets in the United States and developing its novel fumaric acid ester product candidate, XP23829, as a potential treatment for psoriasis and/or relapsing forms of multiple sclerosis, or MS. The Company’s pipeline of product candidates also includes potential treatments for patients with spasticity related to spinal cord injury and Parkinson’s disease. HORIZANT and the Company’s product candidates are prodrugs that are typically created by modifying the chemical structure of currently marketed drugs, referred to as parent drugs, and are designed to correct limitations in the oral absorption, distribution and/or metabolism of the parent drug. HORIZANT and each of the Company’s product candidates are orally-available, patented molecules that address potential markets with clear unmet medical needs. The Company’s facilities are located in Santa Clara, California.
	On November 8, 2012, the Company reached an agreement with Glaxo Group Limited, or GSK, to terminate the Amended and Restated Development and Commercialization Agreement dated November 7, 2010, between the Company and GSK regarding HORIZANT.
	Under the terms of the November 2012 termination and transition agreement, during a transition period that ended on April 30, 2013, GSK continued to exclusively commercialize, promote, manufacture and distribute HORIZANT in the United States. The Company was not eligible to receive any milestone payments from GSK and did not receive any revenue or incur any losses from GSK’s sales of HORIZANT during the transition period. GSK continued to fully fund the costs associated with the management and conduct of required post-marketing clinical studies initiated by GSK prior to the date of the termination and transition agreement. In addition, GSK provided to the Company inventory of gabapentin enacarbil in GSK’s possession that was not required for use by GSK in the manufacture of HORIZANT and related manufacturing property and equipment. In exchange for such inventory, the Company will make annual payments to GSK of $1,000,000 for six years beginning in 2016, which was recorded at its present value as “Other noncurrent liability” on the Company’s balance sheet for the periods ended March 31, 2014 and December 31, 2013 and is being accreted to its contractual value over the payment period. On May 1, 2013, the Company completed the acquisition of the HORIZANT business in accordance with the termination and transition agreement and assumed all responsibilities and associated rights for the further development, manufacturing and commercialization of HORIZANT in the United States on that date. GSK was responsible for the commercial manufacture and supply of HORIZANT during the transition period. The Company did not assume any liabilities of GSK’s HORIZANT business as of the acquisition date.
	On January 29, 2014, the Company completed an underwritten public offering of 12,000,000 shares of its common stock at a price to the public of $6.00 per share. Net cash proceeds from the public offering were approximately $67,300,000, after deducting the underwriting discounts and commissions and offering expenses payable by the Company. On February 21, 2014, the underwriters exercised in full their option to purchase 1,800,000 additional shares resulting in additional net cash proceeds of approximately $10,100,000, after deducting the underwriting discounts and commissions and offering expenses payable by the Company.
	Basis of Preparation
	The accompanying financial statements as of March 31, 2014 and for the three months ended March 31, 2014 and 2013 are unaudited. These unaudited financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s financial position as of March 31, 2014 and comprehensive losses for the three months ended March 31, 2014 and 2013, and cash flows for the three months ended March 31, 2014 and 2013. The Financial Accounting Standards Board, or FASB, Accounting Standards Codification, or the Codification, is the single source of authoritative U.S. generally accepted accounting principles, or GAAP. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from these estimates. The results of operations for the three months ended March 31, 2014 are not necessarily indicative of the results to be expected for the year ending December 31, 2014 or for any other interim period or any other future year. For more complete financial information, these financial statements, and the notes hereto, should be read in conjunction with the audited financial statements for the year ended December 31, 2013 included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission on February 28, 2014. The results of operations of the acquired HORIZANT business, along with the fair values of the assets acquired in the transaction, have been included in the Company’s financial statements since the May 1, 2013 acquisition date.

Collaboration

Collaboration	3 Months Ended
	Mar. 31, 2014
Collaboration	'
	2. Collaboration
	Astellas Pharma Inc.
	In December 2005, the Company entered into an agreement pursuant to which it licensed to Astellas Pharma Inc. exclusive rights to develop and commercialize gabapentin enacarbil in Japan, Korea, the Philippines, Indonesia, Thailand and Taiwan. Astellas commenced commercialization of gabapentin enacarbil in Japan, and began selling gabapentin enacarbil in Japan in July 2012 under the trade name of REGNITE® (gabapentin enacarbil) Extended-Release Tablets. In May 2013, the rights to gabapentin enacarbil in Korea, the Philippines, Indonesia, Thailand and Taiwan reverted to the Company as Astellas notified the Company that it did not have plans for the commercialization of gabapentin enacarbil in these five Asian countries in its territory. In the three months ended March 31, 2014 and 2013, the Company recognized revenue of $283,000 and $379,000, respectively, representing amortization of the up-front license payment under this agreement. In the three months ended March 31, 2014 and 2013, the Company recognized $135,000 and $80,000, respectively, in royalty revenue. As of March 31, 2014, the Company had recognized an aggregate of $52,796,000 of revenue pursuant to this agreement. At March 31, 2014, $12,848,000 of revenue was deferred under this agreement and is being recognized on a straight-line basis over a period that the Company expects to remain obligated to provide services, of which $1,134,000 was classified within current liabilities and the remaining $11,714,000 was recorded as a noncurrent liability.

Acquisition_of_HORIZANT

Acquisition of HORIZANT	3 Months Ended
	Mar. 31, 2014
Acquisition of HORIZANT	'
	3. Acquisition of HORIZANT
	On May 1, 2013, the Company obtained control of, and thus completed the acquisition of, certain assets of HORIZANT that constituted an acquisition of a business as defined under the provisions of the Business Combinations topic. Accordingly, the transaction reflected the recording of the acquisition date fair values of the acquired inventory and manufacturing property and equipment assets. Assets acquired as a result of this transaction were as follows (in thousands):
	Inventories	$	11,733
	Manufacturing property and equipment		1,967
	Total assets acquired	$	13,700
	Inventories were comprised of acquired raw materials, specifically gabapentin enacarbil, and were valued using the cost approach. The cost approach provides a framework for estimating value based on the principle of substitution. The estimated fair value was calculated based on the costs to replace or reproduce the asset, including the cost of recrystallization of the raw material received, while considering any impact on the value of any obsolescence.
	Manufacturing property and equipment acquired included certain equipment and a dedicated manufacturing suite for use in the manufacture of HORIZANT and was recorded at fair value using the replacement cost method. The replacement cost method uses an estimate of the cost of replacing or reproducing an asset to measure value. This amount is then reduced to reflect the amount of depreciation that has accrued given the asset’s age. Other factors and adjustments are considered in concluding on the fair value, including obsolescence of the acquired assets. Depreciation and amortization is computed using the straight-line method over the estimated useful lives of the respective assets, which is ten years.

Net_Loss_per_Share

Net Loss per Share	3 Months Ended
	Mar. 31, 2014
Net Loss per Share	'
	4. Net Loss per Share
	Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period without consideration for potential common shares. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares outstanding for the period plus any dilutive potential common shares for the period determined using the treasury-stock method. For purposes of this calculation, restricted stock units, options to purchase stock and warrants are considered to be potential common shares and are only included in the calculation of diluted net loss per share when their effect is dilutive.
		Three Months
		Ended March 31,
		2014			2013
		(In thousands, except
		per share amounts)
	Numerator:
	Net loss	$	(20,548	)	$	(23,548	)
	Denominator:
	Weighted-average common shares outstanding		56,887			47,249
	Basic and diluted net loss per share	$	(0.36	)	$	(0.50	)
	Outstanding securities at period end not included in the computation of diluted net loss per share as they had an anti-dilutive effect:
	Restricted stock units and options to purchase common stock		8,165			7,151
	Warrants outstanding		—			283
			8,165			7,434

Cash_and_Cash_Equivalents_Shor

Cash and Cash Equivalents, Short-Term Investments and Restricted Investments	3 Months Ended
	Mar. 31, 2014
Cash and Cash Equivalents, Short-Term Investments and Restricted Investments	'
	5. Cash and Cash Equivalents, Short-Term Investments and Restricted Investments
	The carrying amounts of certain of the Company’s financial instruments, including cash, cash equivalents, short-term investments and restricted investments, are stated at fair value. The Company accounts for the fair value of its financial instruments in accordance with the provisions of the Fair Value Measurement topic of the Codification.
	Fair value is the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. The Company applies the market approach valuation technique for fair value measurements on a recurring basis and attempts to maximize the use of observable inputs and minimize the use of unobservable inputs. The fair value hierarchy prioritizes the inputs to valuation techniques used to measure fair value into three broad levels. All of the Company’s cash equivalents and short-term investments are measured using inputs classified at Level 1 or Level 2 within the fair value hierarchy. Level 1 inputs are quoted prices in active markets for identical assets. Level 2 inputs are based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets. Level 3 inputs are unobservable inputs that are supported by little or no market activity and are significant to the fair value of the assets or liabilities. Where applicable, these models project future cash flows and discount the future amounts to a present value using market-based observable inputs obtained from various third-party data providers, including but not limited to, benchmark yields, interest rate curves, reported trades, broker/dealer quotes and market reference data.
	The following are summaries of cash and cash equivalents, short-term investments and restricted investments (in thousands):
		Cost		Gross		Gross			Estimated
				Unrealized		Unrealized			Fair
				Gains		Losses			Value
	As of March 31, 2014:
	Cash	$	6,489	$	—	$	—		$	6,489
	Money market funds		11,329		—		—			11,329
	Corporate debt securities		104,649		26		(30	)		104,645
	Certificates of deposit		1,725		—		—			1,725
		$	124,192	$	26	$	(30	)	$	124,188
	Reported as:
	Cash and cash equivalents								$	17,818
	Short-term investments									104,645
	Restricted investments									1,725
									$	124,188
		Cost		Gross		Gross			Estimated
				Unrealized		Unrealized			Fair
				Gains		Losses			Value
	As of December 31, 2013:
	Cash	$	2,281	$	—	$	—		$	2,281
	Money market funds		10,046		—		—			10,046
	U.S. government-sponsored agencies		2,500		—		—			2,500
	Corporate debt securities		43,831		6		(6	)		43,831
	Certificates of deposit		1,725		—		—			1,725
		$	60,383	$	6	$	(6	)	$	60,383
	Reported as:
	Cash and cash equivalents								$	20,584
	Short-term investments									38,074
	Restricted investments									1,725
									$	60,383
	At March 31, 2014, the contractual maturities of all investments held were less than thirteen months. At December 31, 2013, the contractual maturities of all investments held were less than one year. All investments have been designated as available-for-sale, and changes to unrealized gains and losses are reflected as the only component of accumulated other comprehensive loss. The Company views its available-for-sale portfolio as available for use in current operations. Accordingly, the Company has classified all investments as short-term, even though the stated maturity may be one year or more beyond the current balance sheet date.
	No gross realized gains or losses were recognized and accordingly, there were no amounts reclassified out of accumulated other comprehensive loss to earnings in the three months ended March 31, 2014 or in the same period in 2013.
	The Company’s available-for-sale investments, which include cash equivalents and short-term investments, are measured at fair value on a recurring basis and are classified at the following fair value hierarchy (in thousands):
	Description	Total As of		Fair Value Measurements at Reporting Date Using
		March 31, 2014		Quoted Prices		Significant			Significant
				in Active		Other			Unobservable
				Markets		Observable			Inputs
				for Identical		Inputs			(Level 3)
				Assets		(Level 2)
				(Level 1)
	Money market funds	$	11,329	$	11,329	$	—		$	—
	Corporate debt securities		104,645		—		104,645			—
	Certificates of deposit		1,725		—		1,725			—
	Total	$	117,699	$	11,329	$	106,370		$	—
	Description	Total As of		Fair Value Measurements at Reporting Date Using
		December 31,
		2013		Quoted Prices		Significant			Significant
				in Active		Other			Unobservable
				Markets		Observable			Inputs
				for Identical		Inputs			(Level 3)
				Assets		(Level 2)
				(Level 1)
	Money market funds	$	10,046	$	10,046	$	—		$	—
	U.S. government-sponsored agencies		2,500		—		2,500			—
	Corporate debt securities		43,831		—		43,831			—
	Certificates of deposit		1,725		—		1,725			—
	Total	$	58,102	$	10,046	$	48,056		$	—

Inventories

Inventories	3 Months Ended
	Mar. 31, 2014
Inventories	'
	6. Inventories
	Inventories are stated at the lower of cost or market. Cost is determined on a first-in, first-out, or FIFO, basis. The Company regularly evaluates the Company’s inventories for excess quantities and obsolescence (expiration), taking into account such factors as historical and anticipated future sales compared to quantities on hand and the remaining shelf life of HORIZANT. Write-downs of inventories are considered to be permanent reductions in the cost basis of inventories.
	Inventories that are not expected to be consumed within 12 months following the balance sheet date are classified as long-term inventories.
	Inventories as of March 31, 2014 and December 31, 2013 were as follows (in thousands):
		March 31,		December 31,
		2014		2013
	Raw materials	$	10,024	$	10,258
	Work in progress		443		76
	Finished goods		927		1,113
	Total inventory		11,394		11,447
	Less: Long-term inventories		10,030		10,185
	Total inventory classified as current	$	1,364	$	1,262
	Long-term inventories consist of active pharmaceutical ingredient, or API, of gabapentin enacarbil used for production of HORIZANT. The Company evaluates demand for HORIZANT and expected consumption of the API based on long-term projected sales of HORIZANT.

Other_Accrued_Liabilities

Other Accrued Liabilities	3 Months Ended
	Mar. 31, 2014
Other Accrued Liabilities	'
	7. Other Accrued Liabilities
	Other accrued liabilities at March 31, 2014 and December 31, 2013 were as follows (in thousands):
		March 31,		December 31,
		2014		2013
	Accrued product costs	$	2,034	$	1,903
	Accrued selling and marketing expenses		2,496		883
	Accrued general and administrative expenses		920		632
	Other liabilities		875		520
	Total other accrued liabilities	$	6,325	$	3,938

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2014
Stock-Based Compensation	'
	8. Stock-Based Compensation
	Details of the Company’s employee non-cash stock-based compensation were as follows (in thousands):
		Three Months
		Ended March 31,
		2014		2013
	Research and development	$	702	$	1,196
	Selling, general and administrative		1,982		2,148
		$	2,684	$	3,344

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies	'
	9. Commitments and Contingencies
	On February 10, 2014, Clinton Relational Opportunity Master Fund, L.P., or the Clinton Group, sent a purported advance notice to the Company of its intent to present proposals and to nominate three persons for election to the Company’s board of directors, or the Board, in opposition to the Board’s nominees, at the Company’s 2014 Annual Meeting of Stockholders, or the Annual Meeting. As of the April 15, 2014 record date for the Annual Meeting, the Clinton Group reports that it beneficially owns an aggregate of 1,073,145 shares of the Company’s common stock, constituting approximately 1.7% of the outstanding shares of the Company’s common stock.
	In furtherance of the advance notice delivered to the Company by the Clinton Group on February 10, 2014, the Clinton Group filed a definitive proxy statement with the SEC on April 25, 2014 stating that it intends to solicit proxies to vote in favor of its director nominees and the proposals that it purportedly intends to present before the Annual Meeting. As a result, the Company is facing an opposing proxy solicitation, or the proxy contest, with respect to the matters to be voted on at the Annual Meeting. Costs incurred by the Company in connection with the proxy contest for the three months ended March 31, 2014 totaled approximately $138,000, consisting primarily of outside advisory, legal and proxy solicitor fees. In addition, in its definitive proxy statement with the SEC on April 25, 2014, the Clinton Group stated that its proxy solicitation costs are estimated to be approximately $500,000 and that if the Clinton Group’s proxy solicitation is successful, it may seek reimbursement of these costs from the Company. Due to the inherent uncertainty of the proxy contest, including the potential for litigation to arise or to result from the proxy contest, the Company cannot identify the probable or estimable costs that will ultimately be incurred in connection with such matter.

Organization_and_Summary_of_Si1

Organization and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2014
Basis of Preparation	'
	Basis of Preparation
	The accompanying financial statements as of March 31, 2014 and for the three months ended March 31, 2014 and 2013 are unaudited. These unaudited financial statements have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary to present fairly the Company’s financial position as of March 31, 2014 and comprehensive losses for the three months ended March 31, 2014 and 2013, and cash flows for the three months ended March 31, 2014 and 2013. The Financial Accounting Standards Board, or FASB, Accounting Standards Codification, or the Codification, is the single source of authoritative U.S. generally accepted accounting principles, or GAAP. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from these estimates. The results of operations for the three months ended March 31, 2014 are not necessarily indicative of the results to be expected for the year ending December 31, 2014 or for any other interim period or any other future year. For more complete financial information, these financial statements, and the notes hereto, should be read in conjunction with the audited financial statements for the year ended December 31, 2013 included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission on February 28, 2014. The results of operations of the acquired HORIZANT business, along with the fair values of the assets acquired in the transaction, have been included in the Company’s financial statements since the May 1, 2013 acquisition date.

Acquisition_of_HORIZANT_Tables

Acquisition of HORIZANT (Tables)	3 Months Ended
	Mar. 31, 2014
Assets acquired (Detail)	'
	Assets acquired as a result of this transaction were as follows (in thousands):
	Inventories	$	11,733
	Manufacturing property and equipment		1,967
	Total assets acquired	$	13,700

Net_Loss_per_Share_Tables

Net Loss per Share (Tables)	3 Months Ended
	Mar. 31, 2014
Net Loss Per Share	'
		Three Months
		Ended March 31,
		2014			2013
		(In thousands, except
		per share amounts)
	Numerator:
	Net loss	$	(20,548	)	$	(23,548	)
	Denominator:
	Weighted-average common shares outstanding		56,887			47,249
	Basic and diluted net loss per share	$	(0.36	)	$	(0.50	)
	Outstanding securities at period end not included in the computation of diluted net loss per share as they had an anti-dilutive effect:
	Restricted stock units and options to purchase common stock		8,165			7,151
	Warrants outstanding		—			283
			8,165			7,434

Cash_and_Cash_Equivalents_Shor1

Cash and Cash Equivalents, Short-Term Investments and Restricted Investments (Tables)	3 Months Ended
	Mar. 31, 2014
Cash and Cash Equivalents, Short-Term Investments and Restricted Investments	'
	The following are summaries of cash and cash equivalents, short-term investments and restricted investments (in thousands):
		Cost		Gross		Gross			Estimated
				Unrealized		Unrealized			Fair
				Gains		Losses			Value
	As of March 31, 2014:
	Cash	$	6,489	$	—	$	—		$	6,489
	Money market funds		11,329		—		—			11,329
	Corporate debt securities		104,649		26		(30	)		104,645
	Certificates of deposit		1,725		—		—			1,725
		$	124,192	$	26	$	(30	)	$	124,188
	Reported as:
	Cash and cash equivalents								$	17,818
	Short-term investments									104,645
	Restricted investments									1,725
									$	124,188
		Cost		Gross		Gross			Estimated
				Unrealized		Unrealized			Fair
				Gains		Losses			Value
	As of December 31, 2013:
	Cash	$	2,281	$	—	$	—		$	2,281
	Money market funds		10,046		—		—			10,046
	U.S. government-sponsored agencies		2,500		—		—			2,500
	Corporate debt securities		43,831		6		(6	)		43,831
	Certificates of deposit		1,725		—		—			1,725
		$	60,383	$	6	$	(6	)	$	60,383
	Reported as:
	Cash and cash equivalents								$	20,584
	Short-term investments									38,074
	Restricted investments									1,725
									$	60,383
Available-For-Sale Investments Measured at Fair Value	'
	The Company’s available-for-sale investments, which include cash equivalents and short-term investments, are measured at fair value on a recurring basis and are classified at the following fair value hierarchy (in thousands):
	Description	Total As of		Fair Value Measurements at Reporting Date Using
		March 31, 2014		Quoted Prices		Significant			Significant
				in Active		Other			Unobservable
				Markets		Observable			Inputs
				for Identical		Inputs			(Level 3)
				Assets		(Level 2)
				(Level 1)
	Money market funds	$	11,329	$	11,329	$	—		$	—
	Corporate debt securities		104,645		—		104,645			—
	Certificates of deposit		1,725		—		1,725			—
	Total	$	117,699	$	11,329	$	106,370		$	—
	Description	Total As of		Fair Value Measurements at Reporting Date Using
		December 31,
		2013		Quoted Prices		Significant			Significant
				in Active		Other			Unobservable
				Markets		Observable			Inputs
				for Identical		Inputs			(Level 3)
				Assets		(Level 2)
				(Level 1)
	Money market funds	$	10,046	$	10,046	$	—		$	—
	U.S. government-sponsored agencies		2,500		—		2,500			—
	Corporate debt securities		43,831		—		43,831			—
	Certificates of deposit		1,725		—		1,725			—
	Total	$	58,102	$	10,046	$	48,056		$	—

Inventories_Tables

Inventories (Tables)	3 Months Ended
	Mar. 31, 2014
Inventory	'
	Inventories as of March 31, 2014 and December 31, 2013 were as follows (in thousands):
		March 31,		December 31,
		2014		2013
	Raw materials	$	10,024	$	10,258
	Work in progress		443		76
	Finished goods		927		1,113
	Total inventory		11,394		11,447
	Less: Long-term inventories		10,030		10,185
	Total inventory classified as current	$	1,364	$	1,262

Other_Accrued_Liabilities_Tabl

Other Accrued Liabilities (Tables)	3 Months Ended
	Mar. 31, 2014
Other Accrued Liabilities	'
	Other accrued liabilities at March 31, 2014 and December 31, 2013 were as follows (in thousands):
		March 31,		December 31,
		2014		2013
	Accrued product costs	$	2,034	$	1,903
	Accrued selling and marketing expenses		2,496		883
	Accrued general and administrative expenses		920		632
	Other liabilities		875		520
	Total other accrued liabilities	$	6,325	$	3,938

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2014
Employee Non-Cash Stock-Based Compensation	'
	Details of the Company’s employee non-cash stock-based compensation were as follows (in thousands):
		Three Months
		Ended March 31,
		2014		2013
	Research and development	$	702	$	1,196
	Selling, general and administrative		1,982		2,148
		$	2,684	$	3,344

Organization_and_Summary_of_Si2

Organization and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended	0 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Jan. 29, 2014	Feb. 21, 2014
			Underwritten Public Offering	Underwriters Exercised in full Over-allotment Option
Organization And Summary Of Significant Accounting Policies [Line Items]	'	'	'	'
Annual payment for inventory of gabapentin enacarbil in GSK's possession for six years beginning in 2016	$1,000,000	$1,000,000	'	'
Common stock issued in underwritten public offering	'	'	12,000,000	1,800,000
Common stock price	'	'	$6	'
Net cash proceeds from shares offering	'	'	$67,300,000	$10,100,000

Collaboration_Agreement_Additi

Collaboration Agreement - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'	'
Revenue recognized	$3,375,000	$459,000	'
Royalty revenue	135,000	80,000	'
Deferred revenue, current	1,134,000	'	1,134,000
Deferred revenue, non-current	11,714,000	'	11,997,000
Licensing Agreements | Astellas Pharma Inc.	'	'	'
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'	'
Royalty revenue	135,000	80,000	'
Aggregate revenue recognized	52,796,000	'	'
Deferred revenue	12,848,000	'	'
Deferred revenue, current	1,134,000	'	'
Deferred revenue, non-current	11,714,000	'	'
Licensing Agreements | Astellas Pharma Inc. | Initial license payment	'	'	'
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'	'
Revenue recognized	$283,000	$379,000	'

Assets_Acquired_Detail

Assets Acquired (Detail) (Horizant Business, USD $)	1-May-13
In Thousands, unless otherwise specified
Horizant Business	'
Business Acquisition [Line Items]	'
Inventories	$11,733
Manufacturing property and equipment	1,967
Total assets acquired	$13,700

Net_Loss_Per_Share_Detail

Net Loss Per Share (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Numerator:	'	'
Net loss	($20,548)	($23,548)
Denominator:	'	'
Weighted-average common shares outstanding	56,887	47,249
Basic and diluted net loss per share	($0.36)	($0.50)
Outstanding securities at period end not included in the computation of diluted net loss per share as they had an anti-dilutive effect:	'	'
Outstanding securities not included in the computation of diluted net loss per share	8,165	7,434
Restricted stock units and options to purchase common stock	'	'
Outstanding securities at period end not included in the computation of diluted net loss per share as they had an anti-dilutive effect:	'	'
Outstanding securities not included in the computation of diluted net loss per share	8,165	7,151
Warrants outstanding	'	'
Outstanding securities at period end not included in the computation of diluted net loss per share as they had an anti-dilutive effect:	'	'
Outstanding securities not included in the computation of diluted net loss per share	'	283

Cash_and_Cash_Equivalents_Shor2

Cash and Cash Equivalents, Short-Term Investments and Restricted Investments (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	$124,192	$60,383
Gross Unrealized Gains	26	6
Gross Unrealized Losses	-30	-6
Estimated Fair Value	124,188	60,383
U.S. government-sponsored agencies	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	'	2,500
Estimated Fair Value	'	2,500
Corporate debt securities	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	104,649	43,831
Gross Unrealized Gains	26	6
Gross Unrealized Losses	-30	-6
Estimated Fair Value	104,645	43,831
Certificates of deposit	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	1,725	1,725
Estimated Fair Value	1,725	1,725
Short-term investments	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Estimated Fair Value	104,645	38,074
Restricted investments	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Estimated Fair Value	1,725	1,725
Cash	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	6,489	2,281
Estimated Fair Value	6,489	2,281
Money market funds	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	11,329	10,046
Estimated Fair Value	11,329	10,046
Cash and cash equivalents	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Estimated Fair Value	$17,818	$20,584

Cash_and_Cash_Equivalents_Shor3

Cash and Cash Equivalents, Short-Term Investments and Restricted Investments - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Dec. 31, 2013
			Maximum	Maximum
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'	'	'
Contractual maturities of investments held	'	'	'13 months	'1 year
Gross realized gains or losses recognized	$0	$0	'	'
Amounts reclassified out of accumulated other comprehensive loss to earnings	$0	$0	'	'

AvailableForSale_Investments_M

Available-For-Sale Investments Measured at Fair Value (Detail) (Fair Value Measurements, Recurring basis, USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	$117,699	$58,102
Money market funds	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	11,329	10,046
U.S. government-sponsored agencies	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	'	2,500
Corporate debt securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	104,645	43,831
Certificates of deposit	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	1,725	1,725
Quoted Prices in Active Markets for Identical Assets (Level 1)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	11,329	10,046
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money market funds	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	11,329	10,046
Significant Other Observable Inputs (Level 2)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	106,370	48,056
Significant Other Observable Inputs (Level 2) | U.S. government-sponsored agencies	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	'	2,500
Significant Other Observable Inputs (Level 2) | Corporate debt securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	104,645	43,831
Significant Other Observable Inputs (Level 2) | Certificates of deposit	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	$1,725	$1,725

Inventory_Detail

Inventory (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Inventory [Line Items]	'	'
Raw materials	$10,024	$10,258
Work in progress	443	76
Finished goods	927	1,113
Total inventory	11,394	11,447
Less: Long-term inventories	10,030	10,185
Total inventory classified as current	$1,364	$1,262

Other_Accrued_Liabilities_Deta

Other Accrued Liabilities (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Other Accrued Liabilities [Line Items]	'	'
Accrued product costs	$2,034	$1,903
Accrued selling and marketing expenses	2,496	883
Accrued general and administrative expenses	920	632
Other liabilities	875	520
Total other accrued liabilities	$6,325	$3,938

Employee_NonCash_StockBased_Co

Employee Non-Cash Stock-Based Compensation (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Non-cash stock-based compensation	$2,684	$3,344
Research and development	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Non-cash stock-based compensation	702	1,196
Selling, general and administrative	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Non-cash stock-based compensation	$1,982	$2,148

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Apr. 25, 2014	Apr. 15, 2014
			Subsequent Event	Subsequent Event
				The Clinton Group
Commitments and Contingencies [Line Items]	'	'	'	'
Common stock shares outstanding	61,889,000	47,800,000	'	1,073,145
Percentage of common stock shares owned by minority shareholder	'	'	'	1.70%
Approximate costs incurred in connection with the proxy contest	$138,000	'	$500,000	'