XenoPort (XNPT) 10-Q 8 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 15, 2013
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
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	'	47,736,316

BALANCE_SHEETS

BALANCE SHEETS (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$13,517	$36,134
Short-term investments	60,785	102,868
Accounts receivable, net	867	'
Right to the HORIZANT business	'	13,557
Inventories	1,944	'
Prepaids and other current assets	4,172	2,529
Total current assets	81,285	155,088
Property and equipment, net	2,896	1,528
Long-term inventories	10,341	'
Restricted investments and other assets	1,960	2,432
Total assets	96,482	159,048
Current liabilities:	'	'
Accounts payable	1,277	567
Accrued compensation	4,106	4,875
Accrued restructuring charges	'	993
Accrued preclinical and clinical costs	1,079	4,397
Other accrued liabilities	3,888	1,424
Deferred revenue	1,515	1,515
Total current liabilities	11,865	13,771
Deferred revenue	11,616	12,753
Other noncurrent liability	2,672	2,314
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; 47,733 and 47,068 shares issued and outstanding, at September 30, 2013 and December 31, 2012, respectively	48	47
Additional paid-in capital	588,623	581,741
Accumulated other comprehensive income	3	22
Accumulated deficit	-518,345	-451,600
Total stockholders' equity	70,329	130,210
Total liabilities and stockholders' equity	$96,482	$159,048

BALANCE_SHEETS_Parenthetical

BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
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	47,733	47,068
Common stock, shares outstanding	47,733	47,068

STATEMENTS_OF_COMPREHENSIVE_LO

STATEMENTS OF COMPREHENSIVE LOSS (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues:	'	'	'	'
Product sales, net	$2,037	'	$3,677	'
Collaboration revenue	379	379	1,137	11,137
Royalty revenue	111	'	258	'
Net revenue from unconsolidated joint operating activities	'	'	'	10,000
Total revenues	2,527	379	5,072	21,137
Operating expenses:	'	'	'	'
Cost of product sales	305	'	554	'
Research and development	6,047	9,365	29,636	32,347
Selling, general and administrative	14,928	7,833	41,451	22,822
Total operating expenses	21,280	17,198	71,641	55,169
Loss from operations	-18,753	-16,819	-66,569	-34,032
Interest income	43	66	182	176
Interest expense	-106	'	-358	'
Net loss	-18,816	-16,753	-66,745	-33,856
Other comprehensive loss:	'	'	'	'
Unrealized gains (losses) on available-for-sale securities	20	-17	-19	2
Comprehensive loss	($18,796)	($16,770)	($66,764)	($33,854)
Basic and diluted net loss per share	($0.39)	($0.41)	($1.41)	($0.90)
Shares used to compute basic and diluted net loss per share	47,691	41,016	47,471	37,480

STATEMENTS_OF_CASH_FLOWS

STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Operating activities	'	'
Net loss	($66,745)	($33,856)
Adjustments to reconcile net loss to net cash used in operating activities:	'	'
Depreciation and amortization	870	1,952
Accretion of investment discounts and amortization of investment premiums, net	858	862
Stock-based compensation expense	8,308	9,139
Changes in assets and liabilities:	'	'
Accounts receivable, net	-867	'
Prepaids and other current and noncurrent assets	-1,171	695
Inventories	-552	'
Accounts payable	710	60
Accrued compensation	-769	213
Accrued restructuring charges	-993	-1,332
Accrued preclinical and clinical costs	-3,318	-893
Other accrued liabilities, current and noncurrent	2,679	518
Deferred revenue, current and noncurrent	-1,137	-1,137
Net cash used in operating activities	-62,127	-23,779
Investing activities	'	'
Purchases of investments	-76,817	-102,238
Proceeds from maturities of investments	118,024	76,275
Purchases of property and equipment	-271	-26
Net cash provided by (used in) investing activities	40,936	-25,989
Financing activities	'	'
Net cash proceeds provided by (used in) issuance of common stock and exercise of stock options	-1,426	43,084
Net cash provided by (used in) financing activities	-1,426	43,084
Net decrease in cash and cash equivalents	-22,617	-6,684
Cash and cash equivalents at beginning of period	36,134	25,386
Cash and cash equivalents at end of period	$13,517	$18,702

Organization_and_Summary_of_Si

Organization and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
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 with an initial focus on neurological disorders. The Company is currently commercializing HORIZANT® (gabapentin enacarbil) Extended-Release Tablets in the United States and is developing its novel fumaric acid ester product candidate. The Company also has two internally discovered product candidates that may be developed as treatments for neurological disorders in the future to the extent its resources permit or the Company enters into collaborations with third parties for such development. 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 will continue 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 is recorded as “Other noncurrent liability” on the Company’s balance sheet for the periods ended September 30, 2013 and December 31, 2012. Pursuant to a separate stock purchase agreement, or SPA, entered into between the Company and GSK on November 8, 2012, GSK purchased $20,000,000 of the Company’s common stock, or an aggregate of 1,841,112 shares at $10.863 per share, which per share price represented a 12.5 percent premium to the average of the closing prices of the Company’s common stock for the ten trading days prior to October 31, 2012. In addition, on November 9, 2012, the Company exercised a put option requiring GSK to purchase an additional 2,190,100 shares of the Company’s common stock at $9.132 per share, which per share price represented a 12.5 percent premium to the average of the closing prices of the Company’s common stock for the ten trading days prior to November 9, 2012. 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, and the Company has elected to have GSK continue to supply HORIZANT tablets to the Company for up to six months following the transition period on pricing terms established under the termination and transition agreement. The Company did not assume any liabilities of GSK’s HORIZANT business as of the acquisition date.
	This termination and transition agreement between the Company and GSK also provided for a mutual release of claims and resolved all ongoing litigation between the parties.
	Basis of Preparation
	The accompanying financial statements as of September 30, 2013 and for the three and nine months ended September 30, 2013 and 2012 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 September 30, 2013 and comprehensive losses for the three and nine months ended September 30, 2013 and 2012, and cash flows for the nine months ended September 30, 2013 and 2012. 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 and nine months ended September 30, 2013 are not necessarily indicative of the results to be expected for the year ending December 31, 2013 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, 2012 included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 14, 2013. 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.
	Revenue Recognition
	Product Sales
	The Company began selling HORIZANT to wholesalers in May 2013 following the return of the Company’s commercial rights from GSK. The Company recognizes revenue from HORIZANT product sales when there is persuasive evidence that an arrangement exists, delivery to the customer has occurred, the price is fixed or determinable and collectability is reasonably assured. Revenue from product sales is recorded net of estimated allowances for government rebates such as Medicaid reimbursements, patient assistance programs, customer incentives such as cash discounts for prompt payment, distributor fees and expected returns, as appropriate, which are based on an analysis of historical return rates and deductions of HORIZANT, since its commercial launch by GSK in the second quarter of 2011. Calculating certain of these items involves estimates and judgments based on contractual terms, historical utilization rates data for HORIZANT and new information regarding changes in these programs’ regulations and guidelines that would impact the amount of the actual rebates, the Company’s expectations regarding future utilization rates for these programs and channel inventory data.
	Items Deducted from Gross Product Sales
	Prompt Pay Discount
	The Company offers cash discounts to its customers, generally 2% of the sales price, as an incentive for prompt payment. Based on GSK’s commercialization experience, the Company expects customers to continue to comply with the prompt payment terms to earn the cash discount as the Company is selling HORIZANT to the same customers under similar prompt payment terms and conditions. The Company estimates cash discounts for prompt payment based on contractual terms, GSK’s historical utilization rates and the Company’s expectations regarding future utilization rates. The Company accounts for cash discounts by reducing accounts receivable by the full amount and recognizing the discount as a reduction of revenue in the same period the related revenue is recognized.
	Distributor Fees
	Under the Company’s inventory management agreements with significant wholesalers, the Company pays the wholesalers a fee primarily for distribution services as well as the maintenance of inventory levels. These distributor fees are based on a contractually determined fixed percentage of sales. The Company accrues the contractual amount and recognizes the discount as a reduction of revenue in the same period the related revenue is recognized.
	Product Returns
	The Company does not provide its customers with a general right of product return, but permits returns if the product is damaged or defective when received by the customer, or if the product has or is nearly expired. HORIZANT tablets currently have a shelf-life of 36 months from the date of manufacture. The Company will accept returns for product that will expire within six months or that have expired up to one year after their expiration dates. The Company obtained actual return history by type from GSK since GSK’s product launch in 2011, which provides a basis to reasonably estimate the Company’s future product returns. The Company estimates returns taking into consideration Company-specific adjustments to GSK’s returns history, the shelf life of product, shipment and prescription trends and estimated distribution channel inventory levels.
	Government Rebates
	The Company participates in a number of government rebate programs, such as the Medicaid Drug Rebate Program that provides assistance to eligible low-income patients based on each individual state’s guidelines regarding eligibility and services, Public Health Services or 340b programs, and the Medicare Part D Coverage Gap Discount Program, which provides rebates on prescriptions that fall within the “donut hole” coverage gap; and the Department of Veterans Affairs that offers discounts to authorized users of HORIZANT. HORIZANT is also listed on the Federal Supply Schedule, or “FSS”, of the General Services Administration which provides a discount to the Department of Defense, Department of Veterans Affairs, and TriCare. The Company estimates reductions to the Company’s revenues for government rebate programs based on product pricing, current rebates, GSK’s historical and estimated utilization rates, new information regarding changes in these programs’ regulations and guidelines that would impact the amount of the actual rebates, the Company’s expectations regarding future rebates for these programs and estimated levels of inventory in the distribution channel.
	Patient Assistance
	The Company offers a co-pay card program to assist commercially insured patients with the cost of their HORIZANT related co-payments. Participating retail pharmacies get reimbursed by the Company for the amount of the co-pay assistance provided to eligible patients. The Company estimates and accrues the cost of the co-pay program based on historical redemption activity for this program. The Company reimburses the participating pharmacies approximately one month after the prescriptions subject to co-pay assistance are filled.
	Cost of Product Sales
	Cost of product sales includes direct and indirect costs to manufacture product sold, including tableting, packaging, storage, shipping and handling costs and inventory write-downs, if any.
	Accounts Receivable
	Trade accounts receivable are recorded net of allowances for cash discounts for prompt payment, wholesaler discounts and chargebacks. The need for bad debt allowance is evaluated each reporting period based on the Company’s assessment of the credit worthiness of its customers.
	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 will regularly evaluate 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 twelve months following the balance sheet date are classified as a noncurrent asset.
	Inventories as of September 30, 2013 are summarized as follows (in thousands):
	Raw materials	$	10,333
	Work in progress		1,228
	Finished goods		724
	Total inventory		12,285
	Less: Long-term inventories		10,341
	Total inventory classified as current	$	1,944
	The Company did not have inventories as of December 31, 2012.
	Nonretirement Postemployment Benefits
	On May 31, 2012, the Company adopted the XenoPort Amended and Restated 2012 Severance Plan, or the 2012 Severance Plan, for the benefit of the Company’s non-executive employees. Under the terms of the 2012 Severance Plan, a non-executive employee terminated by the Company because of elimination of his or her position is eligible to receive continuation of medical insurance under COBRA and specified severance payments based on the employee’s level and years of service with the Company. The Company accounts for employee termination benefits in accordance with the provisions of the Compensation-Nonretirement Postemployment Benefits topic of the Codification and records employee termination liabilities once they are both probable and estimable for severance provided under the Company’s existing severance program.
	On June 14, 2013, the Company implemented a reduction in force that included the elimination of certain non-executive positions as the Company completed certain work projects on its arbaclofen placarbil development program. As a result, the Company recorded severance benefits charges of $0 and $703,000 in the three and nine months ended September 30, 2013, respectively, which were included in the “Research and development” line of the “Operating expenses” section of the Company’s statements of comprehensive loss. As of September 30, 2013, the associated liability balance, included within “Accrued compensation” on the Company’s balance sheets, was $275,000.

Collaboration

Collaboration	9 Months Ended
	Sep. 30, 2013
Collaboration	'
	2. Collaboration
	Astellas Pharma Inc.
	In December 2005, the Company entered into an agreement pursuant to which it licensed to Astellas Pharma Inc., or Astellas, 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, Astellas notified the Company that it did not have plans for the commercialization of gabapentin enacarbil in the five other Asian countries in its territory. As a result, in May 2013, the rights to gabapentin enacarbil in Korea, the Philippines, Indonesia, Thailand and Taiwan reverted to the Company. In the three and nine months ended September 30, 2013 and 2012, the Company recognized revenue of $379,000 and $1,137,000, respectively, representing amortization of the up-front license payment under this agreement. In the three months ended March 31, 2012, the Company also recognized a $10,000,000 milestone payment in connection with the approval of REGNITE in Japan. In the three and nine months ended September 30, 2013, the Company recognized $111,000 and $258,000, respectively, in royalty revenue. No royalty revenue was received in the three and nine months ended September 30, 2012. As of September 30, 2013, the Company had recognized an aggregate of $52,236,000 of revenue pursuant to this agreement. At September 30, 2013, $13,131,000 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 $1,515,000 was classified within current liabilities and the remaining $11,616,000 was recorded as a noncurrent liability.

Acquisition_of_HORIZANT

Acquisition of HORIZANT	9 Months Ended
	Sep. 30, 2013
Acquisition of HORIZANT	'
	3. Acquisition of HORIZANT
	The Company accounted for the November 2012 termination and transition agreement and the stock purchase agreement with GSK in accordance with the provisions of the Business Combinations topic of the Codification. Under the provisions of the Business Combinations topic, the acquisition date for a business is the date on which the Company obtains control of the acquiree. The Company obtained control of the HORIZANT business at the end of the transition period, or May 1, 2013. Accordingly, on November 8, 2012, the transaction did not meet the definition of a business combination, and the Company accounted for the transaction as a multiple element arrangement consisting of the settlement of a pre-existing relationship in exchange for the right to acquire the HORIZANT business at the end of a defined transition period, the sale of common stock at a premium and the obligation by the Company to make certain cash payments to GSK in the future. The value of the HORIZANT business was based on an estimated discounted cash flow analysis attributable to the HORIZANT business.
	The following table summarizes the fair value of consideration exchanged as part of the termination and transition agreement (in thousands):
	Cash payable to GSK (recorded as “Other noncurrent liability” on the Company’s balance sheet for the year ended December 31, 2012)		$	2,314
	Issuance of common shares to GSK			30,268
	Cash received for common shares issued to GSK			(40,000	)
	Settlement of litigation with GSK			20,499
	Transaction costs			476
			$	13,557
	The consideration exchanged was recorded in the Company’s financial statements for the year ended December 31, 2012.
	On May 1, 2013, the Company obtained control of and thus completed the acquisition of certain assets of HORIZANT that constituted a business acquisition as defined under the provisions of the Business Combinations topic. Accordingly, the transaction reflected the removal of the right to the HORIZANT business (which was recorded at fair value, as determined by a discounted cash flow analysis, that remained unchanged as of May 1, 2013), and 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 were 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.
	During the three and nine months ended September 30, 2013, the Company incurred $171,000 and $476,000, respectively, in transaction costs related to the HORIZANT business acquisition, which primarily consisted of legal, accounting and valuation-related expenses. These expenses were recorded in the “Selling, general and administrative” line of the “Operating expenses” section of the Company’s statements of comprehensive loss.
	The Company recorded net revenues of $3,677,000 and a net loss of $11,377,000 from the acquired HORIZANT business in the Company’s statements of comprehensive loss from the acquisition date through September 30, 2013.
	The following unaudited supplemental pro forma information summarizes the combined results of operations of the Company and the HORIZANT business as though the acquisition had occurred on January 1, 2012 (in thousands):
			Three Months Ended					Nine Months Ended
			September 30,					September 30,
			2013			2012		2013		2012
	Revenues		$	2,527		$	1,955	$	6,249	$	25,578
	Net loss		$	18,816		$	23,513	$	73,653	$	53,306
	These amounts have been calculated after applying the Company’s accounting policies and adjusting the results of the HORIZANT business to reflect the following adjustments:
		•		An amendment to depreciation expense included in costs of goods sold to reflect the depreciation of the fair value of the acquired manufacturing property and equipment over the estimated remaining useful lives of the respective assets.
		•		The difference between the cost of raw materials known as active pharmaceutical ingredient, or API, that GSK incurred and the Company’s recorded fair value of the API.
		•		The difference in selling expense between GSK direct selling expenses and the Company’s third party contractual costs.
	The pro forma information presented above is for informational purposes only and is not indicative of the results of operations that would have been achieved if the acquisition had taken place at the beginning of January 2012, nor is it indicative of any future results.

Net_Loss_per_Share

Net Loss per Share	9 Months Ended
	Sep. 30, 2013
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						Nine Months
		Ended September 30,						Ended September 30,
		2013			2012			2013			2012
		(In thousands, except per share amounts)
	Numerator:
	Net loss	$	(18,816	)	$	(16,753	)	$	(66,745	)	$	(33,856	)
	Denominator:
	Weighted-average common shares outstanding		47,691			41,016			47,471			37,480
	Basic and diluted net loss per share	$	(0.39	)	$	(0.41	)	$	(1.41	)	$	(0.90	)
	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		6,751			6,374			6,751			6,374
	Warrants outstanding		283			283			283			283
			7,034			6,657			7,034			6,657

Cash_and_Cash_Equivalents_Shor

Cash and Cash Equivalents, Short-Term Investments and Restricted Investments	9 Months Ended
	Sep. 30, 2013
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 and cash equivalents and short-term 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. 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. 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.
	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 September 30, 2013:
	Cash	$	3,752	$	—	$	—		$	3,752
	Money market funds		9,765		—		—			9,765
	U.S. government-sponsored agencies		1,070		—		—			1,070
	Corporate debt securities		59,712		13		(10	)		59,715
	Certificates of deposit		1,725		—		—			1,725
		$	76,024	$	13	$	(10	)	$	76,027
	Reported as:
	Cash and cash equivalents								$	13,517
	Short-term investments									60,785
	Restricted investments									1,725
									$	76,027
		Cost		Gross		Gross			Estimated
				Unrealized		Unrealized			Fair
				Gains		Losses			Value
	As of December 31, 2012:
	Cash	$	915	$	—	$	—		$	915
	Money market funds		20,897		—		—			20,897
	U.S. government-sponsored agencies		11,329		1		—			11,330
	Corporate debt securities		105,839		32		(11	)		105,860
	Certificates of deposit		1,955		—		—			1,955
		$	140,935	$	33	$	(11	)	$	140,957
	Reported as:
	Cash and cash equivalents								$	36,134
	Short-term investments									102,868
	Restricted investments									1,955
									$	140,957
	At September 30, 2013 and December 31, 2012, 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 income. 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 income to earnings in the three or nine months ended September 30, 2013 or in the same periods in 2012.
	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):
				Fair Value Measurements at Reporting Date Using
	Description	Total As of		Quoted Prices in		Significant			Significant
		September 30,		Active Markets		Other			Unobservable
		2013		for Identical		Observable			Inputs
				Assets		Inputs			(Level 3)
				(Level 1)		(Level 2)
	Money market funds	$	9,765	$	9,765	$	—		$	—
	U.S. government-sponsored agencies		1,070		—		1,070			—
	Corporate debt securities		59,715		—		59,715			—
	Total	$	70,550	$	9,765	$	60,785		$	—
				Fair Value Measurements at Reporting Date Using
	Description	Total As of		Quoted Prices in		Significant			Significant
		December,		Active Markets		Other			Unobservable
		2012		for Identical		Observable			Inputs
				Assets		Inputs			(Level 3)
				(Level 1)		(Level 2)
	Money market funds	$	20,897	$	20,897	$	—		$	—
	U.S. government-sponsored agencies		11,330		—		11,330			—
	Corporate debt securities		105,860		—		105,860			—
	Total	$	138,087	$	20,897	$	117,190		$	—

Other_Accrued_Liabilities

Other Accrued Liabilities	9 Months Ended
	Sep. 30, 2013
Other Accrued Liabilities	'
	6. Other Accrued Liabilities
	Other accrued liabilities at September 30, 2013 and December 31, 2012 were as follows (in thousands):
		September 30,		December 31,
		2013		2012
	Accrued product costs	$	1,598	$	—
	Accrued selling and marketing expenses		1,114		276
	Accrued general and administrative expenses		760		1,047
	Other liabilities		416		101
	Total other accrued liabilities	$	3,888	$	1,424

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2013
Stock-Based Compensation	'
	7. Stock-Based Compensation
	Details of the Company’s employee non-cash stock-based compensation were as follows:
		Three Months				Nine Months
		Ended September 30,				Ended September 30,
		2013		2012		2013		2012
		(In thousands)
	Research and development	$	618	$	935	$	2,523	$	3,043
	Selling, general and administrative		1,851		1,881		5,785		6,096
		$	2,469	$	2,816	$	8,308	$	9,139

Organization_and_Summary_of_Si1

Organization and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2013
Basis of Preparation	'
	Basis of Preparation
	The accompanying financial statements as of September 30, 2013 and for the three and nine months ended September 30, 2013 and 2012 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 September 30, 2013 and comprehensive losses for the three and nine months ended September 30, 2013 and 2012, and cash flows for the nine months ended September 30, 2013 and 2012. 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 and nine months ended September 30, 2013 are not necessarily indicative of the results to be expected for the year ending December 31, 2013 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, 2012 included in the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission on March 14, 2013. 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.
Revenue Recognition	'
	Revenue Recognition
	Product Sales
	The Company began selling HORIZANT to wholesalers in May 2013 following the return of the Company’s commercial rights from GSK. The Company recognizes revenue from HORIZANT product sales when there is persuasive evidence that an arrangement exists, delivery to the customer has occurred, the price is fixed or determinable and collectability is reasonably assured. Revenue from product sales is recorded net of estimated allowances for government rebates such as Medicaid reimbursements, patient assistance programs, customer incentives such as cash discounts for prompt payment, distributor fees and expected returns, as appropriate, which are based on an analysis of historical return rates and deductions of HORIZANT, since its commercial launch by GSK in the second quarter of 2011. Calculating certain of these items involves estimates and judgments based on contractual terms, historical utilization rates data for HORIZANT and new information regarding changes in these programs’ regulations and guidelines that would impact the amount of the actual rebates, the Company’s expectations regarding future utilization rates for these programs and channel inventory data.
	Items Deducted from Gross Product Sales
	Prompt Pay Discount
	The Company offers cash discounts to its customers, generally 2% of the sales price, as an incentive for prompt payment. Based on GSK’s commercialization experience, the Company expects customers to continue to comply with the prompt payment terms to earn the cash discount as the Company is selling HORIZANT to the same customers under similar prompt payment terms and conditions. The Company estimates cash discounts for prompt payment based on contractual terms, GSK’s historical utilization rates and the Company’s expectations regarding future utilization rates. The Company accounts for cash discounts by reducing accounts receivable by the full amount and recognizing the discount as a reduction of revenue in the same period the related revenue is recognized.
	Distributor Fees
	Under the Company’s inventory management agreements with significant wholesalers, the Company pays the wholesalers a fee primarily for distribution services as well as the maintenance of inventory levels. These distributor fees are based on a contractually determined fixed percentage of sales. The Company accrues the contractual amount and recognizes the discount as a reduction of revenue in the same period the related revenue is recognized.
	Product Returns
	The Company does not provide its customers with a general right of product return, but permits returns if the product is damaged or defective when received by the customer, or if the product has or is nearly expired. HORIZANT tablets currently have a shelf-life of 36 months from the date of manufacture. The Company will accept returns for product that will expire within six months or that have expired up to one year after their expiration dates. The Company obtained actual return history by type from GSK since GSK’s product launch in 2011, which provides a basis to reasonably estimate the Company’s future product returns. The Company estimates returns taking into consideration Company-specific adjustments to GSK’s returns history, the shelf life of product, shipment and prescription trends and estimated distribution channel inventory levels.
	Government Rebates
	The Company participates in a number of government rebate programs, such as the Medicaid Drug Rebate Program that provides assistance to eligible low-income patients based on each individual state’s guidelines regarding eligibility and services, Public Health Services or 340b programs, and the Medicare Part D Coverage Gap Discount Program, which provides rebates on prescriptions that fall within the “donut hole” coverage gap; and the Department of Veterans Affairs that offers discounts to authorized users of HORIZANT. HORIZANT is also listed on the Federal Supply Schedule, or “FSS”, of the General Services Administration which provides a discount to the Department of Defense, Department of Veterans Affairs, and TriCare. The Company estimates reductions to the Company’s revenues for government rebate programs based on product pricing, current rebates, GSK’s historical and estimated utilization rates, new information regarding changes in these programs’ regulations and guidelines that would impact the amount of the actual rebates, the Company’s expectations regarding future rebates for these programs and estimated levels of inventory in the distribution channel.
	Patient Assistance
	The Company offers a co-pay card program to assist commercially insured patients with the cost of their HORIZANT related co-payments. Participating retail pharmacies get reimbursed by the Company for the amount of the co-pay assistance provided to eligible patients. The Company estimates and accrues the cost of the co-pay program based on historical redemption activity for this program. The Company reimburses the participating pharmacies approximately one month after the prescriptions subject to co-pay assistance are filled.
Cost of Product Sales	'
	Cost of Product Sales
	Cost of product sales includes direct and indirect costs to manufacture product sold, including tableting, packaging, storage, shipping and handling costs and inventory write-downs, if any.
Accounts Receivable	'
	Accounts Receivable
	Trade accounts receivable are recorded net of allowances for cash discounts for prompt payment, wholesaler discounts and chargebacks. The need for bad debt allowance is evaluated each reporting period based on the Company’s assessment of the credit worthiness of its customers.
Inventories	'
	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 will regularly evaluate 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 twelve months following the balance sheet date are classified as a noncurrent asset.
	Inventories as of September 30, 2013 are summarized as follows (in thousands):
	Raw materials	$	10,333
	Work in progress		1,228
	Finished goods		724
	Total inventory		12,285
	Less: Long-term inventories		10,341
	Total inventory classified as current	$	1,944
	The Company did not have inventories as of December 31, 2012.
Nonretirement Postemployment Benefits	'
	Nonretirement Postemployment Benefits
	On May 31, 2012, the Company adopted the XenoPort Amended and Restated 2012 Severance Plan, or the 2012 Severance Plan, for the benefit of the Company’s non-executive employees. Under the terms of the 2012 Severance Plan, a non-executive employee terminated by the Company because of elimination of his or her position is eligible to receive continuation of medical insurance under COBRA and specified severance payments based on the employee’s level and years of service with the Company. The Company accounts for employee termination benefits in accordance with the provisions of the Compensation-Nonretirement Postemployment Benefits topic of the Codification and records employee termination liabilities once they are both probable and estimable for severance provided under the Company’s existing severance program.
	On June 14, 2013, the Company implemented a reduction in force that included the elimination of certain non-executive positions as the Company completed certain work projects on its arbaclofen placarbil development program. As a result, the Company recorded severance benefits charges of $0 and $703,000 in the three and nine months ended September 30, 2013, respectively, which were included in the “Research and development” line of the “Operating expenses” section of the Company’s statements of comprehensive loss. As of September 30, 2013, the associated liability balance, included within “Accrued compensation” on the Company’s balance sheets, was $275,000.

Organization_and_Summary_of_Si2

Organization and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2013
Inventory	'
	Inventories as of September 30, 2013 are summarized as follows (in thousands):
	Raw materials	$	10,333
	Work in progress		1,228
	Finished goods		724
	Total inventory		12,285
	Less: Long-term inventories		10,341
	Total inventory classified as current	$	1,944

Acquisition_of_HORIZANT_Tables

Acquisition of HORIZANT (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value of Net Identified Assets Acquired and Consideration Transferred	'
	The following table summarizes the fair value of consideration exchanged as part of the termination and transition agreement (in thousands):
	Cash payable to GSK (recorded as “Other noncurrent liability” on the Company’s balance sheet for the year ended December 31, 2012)	$	2,314
	Issuance of common shares to GSK		30,268
	Cash received for common shares issued to GSK		(40,000	)
	Settlement of litigation with GSK		20,499
	Transaction costs		476
		$	13,557
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
Proforma Consolidated Revenues and Net Loss	'
	The following unaudited supplemental pro forma information summarizes the combined results of operations of the Company and the HORIZANT business as though the acquisition had occurred on January 1, 2012 (in thousands):
		Three Months Ended					Nine Months Ended
		September 30,					September 30,
		2013			2012		2013		2012
	Revenues	$	2,527		$	1,955	$	6,249	$	25,578
	Net loss	$	18,816		$	23,513	$	73,653	$	53,306

Net_Loss_per_Share_Tables

Net Loss per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Net Income (Loss) Per Share	'
		Three Months						Nine Months
		Ended September 30,						Ended September 30,
		2013			2012			2013			2012
		(In thousands, except per share amounts)
	Numerator:
	Net loss	$	(18,816	)	$	(16,753	)	$	(66,745	)	$	(33,856	)
	Denominator:
	Weighted-average common shares outstanding		47,691			41,016			47,471			37,480
	Basic and diluted net loss per share	$	(0.39	)	$	(0.41	)	$	(1.41	)	$	(0.90	)
	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		6,751			6,374			6,751			6,374
	Warrants outstanding		283			283			283			283
			7,034			6,657			7,034			6,657

Cash_and_Cash_Equivalents_Shor1

Cash and Cash Equivalents, Short-Term Investments and Restricted Investments (Tables)	9 Months Ended
	Sep. 30, 2013
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 September 30, 2013:
	Cash	$	3,752	$	—	$	—		$	3,752
	Money market funds		9,765		—		—			9,765
	U.S. government-sponsored agencies		1,070		—		—			1,070
	Corporate debt securities		59,712		13		(10	)		59,715
	Certificates of deposit		1,725		—		—			1,725
		$	76,024	$	13	$	(10	)	$	76,027
	Reported as:
	Cash and cash equivalents								$	13,517
	Short-term investments									60,785
	Restricted investments									1,725
									$	76,027
		Cost		Gross		Gross			Estimated
				Unrealized		Unrealized			Fair
				Gains		Losses			Value
	As of December 31, 2012:
	Cash	$	915	$	—	$	—		$	915
	Money market funds		20,897		—		—			20,897
	U.S. government-sponsored agencies		11,329		1		—			11,330
	Corporate debt securities		105,839		32		(11	)		105,860
	Certificates of deposit		1,955		—		—			1,955
		$	140,935	$	33	$	(11	)	$	140,957
	Reported as:
	Cash and cash equivalents								$	36,134
	Short-term investments									102,868
	Restricted investments									1,955
									$	140,957
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):
				Fair Value Measurements at Reporting Date Using
	Description	Total As of		Quoted Prices in		Significant			Significant
		September 30,		Active Markets		Other			Unobservable
		2013		for Identical		Observable			Inputs
				Assets		Inputs			(Level 3)
				(Level 1)		(Level 2)
	Money market funds	$	9,765	$	9,765	$	—		$	—
	U.S. government-sponsored agencies		1,070		—		1,070			—
	Corporate debt securities		59,715		—		59,715			—
	Total	$	70,550	$	9,765	$	60,785		$	—
				Fair Value Measurements at Reporting Date Using
	Description	Total As of		Quoted Prices in		Significant			Significant
		December,		Active Markets		Other			Unobservable
		2012		for Identical		Observable			Inputs
				Assets		Inputs			(Level 3)
				(Level 1)		(Level 2)
	Money market funds	$	20,897	$	20,897	$	—		$	—
	U.S. government-sponsored agencies		11,330		—		11,330			—
	Corporate debt securities		105,860		—		105,860			—
	Total	$	138,087	$	20,897	$	117,190		$	—

Other_Accrued_Liabilities_Tabl

Other Accrued Liabilities (Tables)	9 Months Ended
	Sep. 30, 2013
Other Accrued Liabilities	'
	Other accrued liabilities at September 30, 2013 and December 31, 2012 were as follows (in thousands):
		September 30,		December 31,
		2013		2012
	Accrued product costs	$	1,598	$	—
	Accrued selling and marketing expenses		1,114		276
	Accrued general and administrative expenses		760		1,047
	Other liabilities		416		101
	Total other accrued liabilities	$	3,888	$	1,424

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Employee Non-Cash Stock-Based Compensation	'
	Details of the Company’s employee non-cash stock-based compensation were as follows:
		Three Months				Nine Months
		Ended September 30,				Ended September 30,
		2013		2012		2013		2012
		(In thousands)
	Research and development	$	618	$	935	$	2,523	$	3,043
	Selling, general and administrative		1,851		1,881		5,785		6,096
		$	2,469	$	2,816	$	8,308	$	9,139

Organization_and_Summary_of_Si3

Organization and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended		9 Months Ended	12 Months Ended	3 Months Ended	9 Months Ended	0 Months Ended
	Nov. 09, 2012	Oct. 31, 2012	Nov. 08, 2012	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013	Nov. 08, 2012	Nov. 09, 2012
	D	D				Nonretirement Postemployment Benefits	Nonretirement Postemployment Benefits	Glaxo Group Limited	Glaxo Group Limited
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	'	'	'	'
Proceed from issuance of common stock	'	'	40,000,000	'	'	'	'	20,000,000	20,000,000
Stock issued, shares	'	'	'	'	'	'	'	1,841,112	2,190,100
Stock issued, price per-shares	'	'	'	'	'	'	'	$10.86	$9.13
Percentage of stock issue price over average stock closing price	12.50%	'	12.50%	'	'	'	'	'	'
Common Stock Trading Days to be Considered For Valuation	10	10	'	'	'	'	'	'	'
Cash discount offers to customers	'	'	'	2.00%	'	'	'	'	'
Severance benefits charges	'	'	'	'	'	0	703,000	'	'
Accrued compensation	'	'	'	$4,106,000	$4,875,000	$275,000	$275,000	'	'

Inventory_Detail

Inventory (Detail) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Organization And Summary Of Significant Accounting Policies [Line Items]	'
Raw materials	$10,333
Work in progress	1,228
Finished goods	724
Total inventory	12,285
Less: Long-term inventories	10,341
Total inventory classified as current	$1,944

Collaboration_Agreement_Additi

Collaboration Agreement - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended	94 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Mar. 31, 2012	Sep. 30, 2013	Sep. 30, 2012
						Licensing Agreements	Licensing Agreements	Licensing Agreements	Licensing Agreements	Licensing Agreements	Licensing Agreements
						Astellas Pharma Inc.	Astellas Pharma Inc.	Astellas Pharma Inc.	Astellas Pharma Inc.	Astellas Pharma Inc.	Astellas Pharma Inc.
									Approval of Regnite in Japan	Initial license payment	Initial license payment
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Revenue recognized	$2,527,000	$379,000	$5,072,000	$21,137,000	'	'	'	$52,236,000	$10,000,000	$379,000	$1,137,000
Royalty revenue	111,000	'	258,000	'	'	111,000	258,000	'	'	'	'
Deferred revenue	'	'	'	'	'	13,131,000	13,131,000	13,131,000	'	'	'
Deferred revenue, current	1,515,000	'	1,515,000	'	1,515,000	1,515,000	1,515,000	1,515,000	'	'	'
Deferred revenue, non-current	$11,616,000	'	$11,616,000	'	$12,753,000	$11,616,000	$11,616,000	$11,616,000	'	'	'

Fair_Value_of_Net_Identifiable

Fair Value of Net Identifiable Assets Acquired and Consideration Transferred (Detail) (USD $)	1 Months Ended
In Thousands, unless otherwise specified	Nov. 08, 2012
Business Acquisition [Line Items]	'
Cash payable to GSK (recorded as "Other noncurrent liability" on the Company's balance sheet for the year ended December 31, 2012)	$2,314
Issuance of common shares to GSK	30,268
Cash received for common shares issued to GSK	-40,000
Settlement of litigation with GSK	20,499
Transaction costs	476
Consideration transferred , total	$13,557

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

Acquisitions_of_Horizant_Addit

Acquisitions of Horizant - Additional Information (Detail) (Horizant Business, USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013
Horizant Business	'	'
Business Acquisition [Line Items]	'	'
Transaction costs	$171,000	$476,000
Revenues	'	3,677,000
Net loss	'	($11,377,000)

Proforma_Consolidated_Revenue_

Proforma Consolidated Revenue and Net Loss (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Business Acquisition [Line Items]	'	'	'	'
Revenues	$2,527	$1,955	$6,249	$25,578
Net loss	$18,816	$23,513	$73,653	$53,306

Net_Loss_Per_Share_Detail

Net Loss Per Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator:	'	'	'	'
Net loss	($18,816)	($16,753)	($66,745)	($33,856)
Denominator:	'	'	'	'
Weighted-average common shares outstanding	47,691	41,016	47,471	37,480
Basic and diluted net loss per share	($0.39)	($0.41)	($1.41)	($0.90)
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	7,034	6,657	7,034	6,657
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	6,751	6,374	6,751	6,374
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	283	283	283

Cash_and_Cash_Equivalents_Shor2

Cash and Cash Equivalents, Short-Term Investments and Restricted Investments (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	$76,024	$140,935
Gross Unrealized Gains	13	33
Gross Unrealized Losses	-10	-11
Estimated Fair Value	76,027	140,957
U.S. government-sponsored agencies	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	1,070	11,329
Gross Unrealized Gains	'	1
Estimated Fair Value	1,070	11,330
Corporate debt securities	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	59,712	105,839
Gross Unrealized Gains	13	32
Gross Unrealized Losses	-10	-11
Estimated Fair Value	59,715	105,860
Certificates of deposit	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	1,725	1,955
Estimated Fair Value	1,725	1,955
Short-term investments	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Estimated Fair Value	60,785	102,868
Restricted investments	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Estimated Fair Value	1,725	1,955
Cash	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	3,752	915
Estimated Fair Value	3,752	915
Money market funds	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Cost	9,765	20,897
Estimated Fair Value	9,765	20,897
Cash and cash equivalents	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Estimated Fair Value	$13,517	$36,134

Cash_and_Cash_Equivalents_Shor3

Cash and Cash Equivalents, Short-Term Investments and Restricted Investments - Additional Information (Detail) (Maximum)	Sep. 30, 2013	Dec. 31, 2012
Maximum	'	'
Cash Cash Equivalents Short Term Investments and Restricted Investments [Line Items]	'	'
Contractual maturities of investments held	'1 year	'1 year

AvailableForSale_Investments_M

Available-For-Sale Investments Measured at Fair Value (Detail) (Fair Value Measurements, Recurring basis, USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	$70,550	$138,087
Money market funds	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	9,765	20,897
U.S. government-sponsored agencies	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	1,070	11,330
Corporate debt securities	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	59,715	105,860
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	9,765	20,897
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	9,765	20,897
Significant Other Observable Inputs (Level 2)	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale investments	60,785	117,190
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	1,070	11,330
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	$59,715	$105,860

Other_Accrued_Liabilities_Deta

Other Accrued Liabilities (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Other Accrued Liabilities [Line Items]	'	'
Accrued product costs	$1,598	'
Accrued selling and marketing expenses	1,114	276
Accrued general and administrative expenses	760	1,047
Other liabilities	416	101
Total other accrued liabilities	$3,888	$1,424

Employee_NonCash_StockBased_Co

Employee Non-Cash Stock-Based Compensation (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Non-cash stock-based compensation	$2,469	$2,816	$8,308	$9,139
Research and development	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Non-cash stock-based compensation	618	935	2,523	3,043
Selling, general and administrative	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Non-cash stock-based compensation	$1,851	$1,881	$5,785	$6,096