Acorda Therapeutics (ACORQ) 10-Q 7 Aug 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Jun. 30, 2014	Jul. 31, 2014
Document and Entity Information	'	'
Entity Registrant Name	'ACORDA THERAPEUTICS INC	'
Entity Central Index Key	'0001008848	'
Document Type	'10-Q	'
Document Period End Date	30-Jun-14	'
Amendment Flag	'false	'
Current Fiscal Year End Date	'--12-31	'
Entity Current Reporting Status	'Yes	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	41,744,929
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$274,599	$48,037
Restricted cash	'	277
Short-term investments	331,254	225,891
Trade accounts receivable, net of allowances of $914 and $698, as of June 30, 2014 and December 31, 2013, respectively	27,027	30,784
Prepaid expenses	8,272	8,398
Finished goods inventory held by the Company	30,821	25,535
Finished goods inventory held by others	580	637
Deferred tax asset	10,452	19,314
Other current assets	10,124	8,460
Total current assets	693,129	367,333
Long-term investments	121,855	93,299
Property and equipment, net of accumulated depreciation	15,823	16,525
Deferred tax asset	84,885	107,985
Intangible assets, net of accumulated amortization	17,281	17,459
Non-current portion of deferred cost of license revenue	3,857	4,174
Other assets	6,487	352
Total assets	943,317	607,127
Current liabilities:	'	'
Accounts payable	20,660	15,922
Accrued expenses and other current liabilities	34,064	37,569
Deferred product revenue-Zanaflex	29,462	32,090
Current portion of deferred license revenue	9,057	9,057
Current portion of revenue interest liability	225	861
Current portion of convertible notes payable	1,144	1,144
Total current liabilities	94,612	96,643
Convertible senior notes (due 2021)	283,948	'
Non-current portion of deferred license revenue	55,099	59,628
Put/call liability	167	147
Non-current portion of revenue interest liability	258	493
Non-current portion of convertible notes payable	2,135	3,228
Other non-current liabilities	6,719	6,635
Commitments and contingencies	'	'
Stockholders' equity:	'	'
Common stock, $0.001 par value. Authorized 80,000,000 shares at June 30, 2014 and December 31, 2013; issued and outstanding 41,072,916 and 40,896,355 shares, including those held in treasury, as of June 30, 2014 and December 31, 2013, respectively	41	41
Treasury stock at cost (12,420 shares at June 30, 2014 and December 31, 2013)	-329	-329
Additional paid-in capital	733,265	678,686
Accumulated deficit	-232,694	-238,082
Accumulated other comprehensive income	96	37
Total stockholders' equity	500,379	440,353
Total liabilities and stockholders' equity	$943,317	$607,127

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Consolidated Balance Sheets	'	'
Trade accounts receivable, allowances (in dollars)	$914	$698
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, Authorized shares	80,000,000	80,000,000
Common stock, issued shares	41,072,916	40,896,355
Common stock, outstanding shares	41,072,916	40,896,355
Treasury stock, shares	12,420	12,420

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenues:	'	'	'	'
Net product revenues	$89,719	$80,125	$164,182	$144,209
Royalty revenues	5,146	4,664	8,937	10,180
License revenue	2,264	2,264	4,529	4,529
Total net revenues	97,129	87,053	177,648	158,918
Costs and expenses:	'	'	'	'
Cost of sales	18,899	16,935	34,428	30,418
Cost of license revenue	159	159	317	317
Research and development	16,448	13,216	30,970	25,736
Selling, general and administrative	50,644	48,003	97,537	96,202
Total operating expenses	86,150	78,313	163,252	152,673
Operating income	10,979	8,740	14,396	6,245
Other expense (net):	'	'	'	'
Interest and amortization of debt discount expense	-426	-749	-518	-1,340
Interest income	165	166	337	339
Total other expense (net)	-261	-583	-181	-1,001
Income before taxes	10,718	8,157	14,215	5,244
Provision for income taxes	-6,033	-4,247	-8,825	-2,472
Net income	$4,685	$3,910	$5,390	$2,772
Net income per share-basic (in dollars per share)	$0.11	$0.10	$0.13	$0.07
Net income per share-diluted (in dollars per share)	$0.11	$0.09	$0.13	$0.07
Weighted average common shares outstanding used in computing net income per share-basic (in shares)	41,032	39,960	40,985	39,896
Weighted average common shares outstanding used in computing net income per share-diluted (in shares)	42,432	41,583	42,336	41,311

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Consolidated Statements of Comprehensive Income	'	'	'	'
Net income	$4,685	$3,910	$5,390	$2,772
Other comprehensive income (loss):	'	'	'	'
Unrealized losses on available for sale securities, net of tax	14	-29	59	-8
Other comprehensive income (loss), net of tax	14	-29	59	-8
Comprehensive income	$4,699	$3,881	$5,449	$2,764

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:	'	'
Net income	$5,390	$2,772
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Share-based compensation expense	13,373	11,471
Amortization of net premiums and discounts on investments	1,487	1,169
Amortization of debt discount and debt issuance costs	157	'
Amortization of revenue interest issuance cost	12	28
Depreciation and amortization expense	3,624	2,912
Loss (gain) on put/call liability	20	-329
Deferred tax provision	8,863	2,339
Changes in assets and liabilities:	'	'
Decrease (increase) in accounts receivable	3,757	-728
Increase in prepaid expenses and other current assets	-1,538	-1,371
Increase in inventory held by the Company	-5,287	-10,820
Decrease in inventory held by others	57	87
Decrease in non-current portion of deferred cost of license revenue	317	317
Decrease in other assets	17	17
Increase (decrease) in accounts payable, accrued expenses, other current liabilities	134	-3,942
(Decrease) increase in revenue interest liability interest payable	-510	216
Decrease in non-current portion of deferred license revenue	-4,528	-4,528
Increase (decrease) in other non-current liabilities	18	-107
(Decrease) increase in deferred product revenue-Zanaflex	-2,628	811
Decrease in restricted cash	277	339
Net cash provided by operating activities	23,012	653
Cash flows from investing activities:	'	'
Purchases of property and equipment	-1,390	-2,728
Purchases of intangible assets	-1,286	-1,664
Purchases of investments	-263,848	-59,541
Proceeds from maturities of investments	128,500	60,000
Net cash used in investing activities	-138,024	-3,933
Cash flows from financing activities:	'	'
Proceeds from issuance of convertible senior notes	345,000	'
Debt issuance costs	-7,441	'
Proceeds from issuance of common stock and option exercises	4,375	4,640
Repayments of revenue interest liability	-360	-534
Net cash provided by financing activities	341,574	4,106
Net increase in cash and cash equivalents	226,562	826
Cash and cash equivalents at beginning of period	48,037	41,876
Cash and cash equivalents at end of period	274,599	42,702
Supplemental disclosure:	'	'
Cash paid for interest	706	1,059
Cash paid for taxes	$1,214	$1,337

Organization_and_Business_Acti

Organization and Business Activities	6 Months Ended
	Jun. 30, 2014
Organization and Business Activities	'
Organization and Business Activities	'
	(1) Organization and Business Activities
	Acorda Therapeutics, Inc. (“Acorda” or the “Company”) is a biopharmaceutical company dedicated to the identification, development and commercialization of novel therapies to improve the lives of people with multiple sclerosis (MS), spinal cord injury (SCI) and other neurological disorders.
	The management of the Company is responsible for the accompanying unaudited interim consolidated financial statements and the related information included in the notes to the consolidated financial statements. In the opinion of management, the unaudited interim consolidated financial statements reflect all adjustments, including normal recurring adjustments necessary for the fair presentation of the Company’s financial position and results of operations and cash flows for the periods presented. Results of operations for interim periods are not necessarily indicative of the results to be expected for the entire year.
	These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements of the Company as of and for the year ended December 31, 2013 included in the Company’s Annual Report on Form 10-K for such year, as filed with the Securities and Exchange Commission (the SEC).

Summary_of_Significant_Account

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2014
Summary of Significant Accounting Policies	'
Summary of Significant Accounting Policies	'
	(2) Summary of Significant Accounting Policies
	Principles of Consolidation
	The accompanying consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America and include the results of operations of the Company and its majority owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
	Use of Estimates
	The preparation of the consolidated financial statements requires management of the Company to make a number of estimates and assumptions relating to the reported amount of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the period. Significant items subject to such estimates and assumptions include share-based compensation accounting, which are largely dependent on the fair value of the Company’s equity securities. In addition, the Company recognizes Zanaflex revenue based on estimated prescriptions filled. The Company adjusts its Zanaflex inventory value based on an estimate of inventory that may be returned. Actual results could differ from those estimates.
	Investments
	Both short-term and long-term investments consist of US Treasury bonds. The Company classifies marketable securities available to fund current operations as short-term investments in current assets on its consolidated balance sheets. Marketable securities are classified as long-term investments in long-term assets on the consolidated balance sheets if the Company has the ability and intent to hold them and such holding period is longer than one year. The Company classifies its short-term and long-term investments as available-for-sale. Available-for-sale securities are recorded at fair value of the investments based on quoted market prices.
	Unrealized holding gains and losses on available-for-sale securities, which are determined to be temporary, are excluded from earnings and are reported as a separate component of accumulated other comprehensive income (loss).
	Premiums and discounts on investments are amortized over the life of the related available-for-sale security as an adjustment to yield using the effective-interest method. Dividend and interest income are recognized when earned. Amortized premiums and discounts, dividend and interest income and realized gains and losses are included in interest income.
	Accumulated Other Comprehensive Income
	The Company’s accumulated other comprehensive income is comprised of gains and losses on available for sale securities and is recorded and presented net of income tax.
	Revenue Recognition
	Ampyra
	Ampyra is available only through a network of specialty pharmacy providers that provide the medication to patients by mail; Kaiser Permanente, which distributes Ampyra to patients through a closed network of on-site pharmacies; and ASD Specialty Healthcare, Inc. (an AmerisourceBergen affiliate), which distributes Ampyra to the U.S. Bureau of Prisons and the U.S. Department of Veterans Affairs (VA). Ampyra is not available in retail pharmacies. The Company does not recognize revenue from product sales until there is persuasive evidence of an arrangement, delivery has occurred, the price is fixed and determinable, the buyer is obligated to pay the Company, the obligation to pay is not contingent on resale of the product, the buyer has economic substance apart from the Company, the Company has no obligation to bring about the sale of the product, the amount of returns can be reasonably estimated and collectability is reasonably assured. The Company recognizes product sales of Ampyra following shipment of product to a network of specialty pharmacy providers, Kaiser Permanente, and the specialty distributor to the VA. The specialty pharmacy providers, Kaiser Permanente, and the specialty distributor to the VA are contractually obligated to hold no more than an agreed number of days of inventory, ranging from 10 to 30 days.
	The Company’s net revenues represent total revenues less allowances for customer credits, including estimated discounts, rebates, and chargebacks. These allowances are recorded for cash consideration given by a vendor to a customer that is presumed to be a reduction of the selling prices of the vendor’s products or services and, therefore, are characterized as a reduction of revenue. At the time product is shipped to specialty pharmacies, Kaiser Permanente and the specialty distributor to the VA, an adjustment is recorded for estimated discounts, rebates, and chargebacks. These allowances are established by management as its best estimate based on available information and will be adjusted to reflect known changes in the factors that impact such allowances. Allowances for discounts, rebates, returns and chargebacks are established based on the contractual terms with customers, historical trends, communications with customers and the levels of inventory remaining in the distribution channel, as well as expectations about the market for the product and anticipated introduction of competitive products.  Product shipping and handling costs are included in cost of sales.  The Company does not accept returns of Ampyra with the exception of product damages that occur during shipping.
	Zanaflex
	The Company applies the revenue recognition guidance in Accounting Standards Codification (ASC) 605-15-25, which among other criteria requires that future returns can be reasonably estimated in order to recognize revenue. The amount of future tablet returns is uncertain due to generic competition and customer conversion to Zanaflex Capsules. The Company has accumulated some sales history with Zanaflex Capsules; however, due to existing and potential generic competition and customer conversion from Zanaflex tablets to Zanaflex Capsules, we do not believe we can reasonably determine a return rate at this time. As a result, the Company accounts for these product shipments using a deferred revenue recognition model. Under the deferred revenue model, the Company does not recognize revenue upon product shipment. For these product shipments, the Company invoices the wholesaler, records deferred revenue at gross invoice sales price, and classifies the cost basis of the product held by the wholesaler as a component of inventory. The Company recognizes revenue when prescribed to the end-user, on a first-in first-out (FIFO) basis. The Company’s revenue to be recognized is based on (1) the estimated prescription demand, based on pharmacy sales for its products; and (2) the Company’s analysis of third-party information, including third-party market research data. The Company’s estimates are subject to the inherent limitations of estimates that rely on third-party data, as certain third-party information is itself in the form of estimates, and reflect other limitations. The Company’s sales and revenue recognition reflects the Company’s estimates of actual product prescribed to the end-user. The Company expects to be able to apply a more traditional revenue recognition policy such that revenue is recognized following shipment to the customer when it believes it has sufficient data to develop reasonable estimates of expected returns based upon historical returns and greater certainty regarding generic competition.
	The Company’s net revenues represent total revenues less allowances for customer credits, including estimated discounts, rebates, and chargebacks. These allowances are recorded for cash consideration given by a vendor to a customer that is presumed to be a reduction of the selling prices of the vendor’s products or services and, therefore, should be characterized as a reduction of revenue when recognized in the vendor’s statement of operations. Adjustments are recorded for estimated chargebacks, rebates, and discounts. These allowances are established by management as its best estimate based on available information and are adjusted to reflect known changes in the factors that impact such allowances. Allowances for chargebacks, rebates and discounts are established based on the contractual terms with customers, analysis of historical levels of discounts, chargebacks and rebates, communications with customers and the levels of inventory remaining in the distribution channel, as well as expectations about the market for each product and anticipated introduction of competitive products. In addition, the Company records a charge to cost of goods sold for the cost basis of the estimated product returns the Company believes may ultimately be realized at the time of product shipment to wholesalers. The Company has recognized this charge at the date of shipment since it is probable that it will receive a level of returned products; upon the return of such product it will be unable to resell the product considering its expiration dating; and it can reasonably estimate a range of returns. This charge represents the cost basis for the low end of the range of the Company’s estimated returns. Product shipping and handling costs are included in cost of sales.
	Qutenza
	Qutenza is distributed in the United States by Besse Medical, Inc., a specialty distributor that furnishes the medication to physician offices; and by ASD Specialty Healthcare, Inc., a specialty distributor that furnishes the medication to hospitals and clinics. The Company does not recognize revenue from product sales until there is persuasive evidence of an arrangement, delivery has occurred, the price is fixed and determinable, the buyer is obligated to pay the Company, the obligation to pay is not contingent on resale of the product, the buyer has economic substance apart from the Company, the Company has no obligation to bring about the sale of the product, and the amount of returns can be reasonably estimated and collectability is reasonably assured. This means that, for Qutenza, the Company recognizes product sales following shipment of product to its specialty distributors.
	The Company’s net revenues represent total revenues less allowances for customer credits, including estimated rebates, chargebacks, and returns. These allowances are recorded for cash consideration given by a vendor to a customer that is presumed to be a reduction of the selling prices of the vendor’s products or services and, therefore, are characterized as a reduction of revenue. At the time product is shipped, an adjustment is recorded for estimated rebates, chargebacks, and returns. These allowances are established by management as its best estimate based on available information and will be adjusted to reflect known changes in the factors that impact such allowances. Allowances for rebates, chargebacks, and returns are established based on the contractual terms with customers, historical trends, as well as expectations about the market for the product and anticipated introduction of competitive products.  Product shipping and handling costs are included in cost of sales.
	Milestones and royalties
	In order to determine the revenue recognition for contingent milestones, the Company evaluates the contingent milestones using the criteria as provided by the Financial Accounting Standards Boards (FASB) guidance on the milestone method of revenue recognition. At the inception of a collaboration agreement the Company evaluates if payments are substantive.  The criteria requires that (i) the Company determines if the milestone is commensurate with either its performance to achieve the milestone or the enhancement of value resulting from the Company’s activities to achieve the milestone, (ii) the milestone be related to past performance, and (iii) the milestone be reasonable relative to all deliverable and payment terms of the collaboration arrangement.  If these criteria are met then the contingent milestones can be considered substantive milestones and will be recognized as revenue in the period that the milestone is achieved. Royalties are recognized as earned in accordance with the terms of various research and collaboration agreements.
	In-Process Research and Development
	The cost of in-process research and development (IPR&D) acquired directly in a transaction other than a business combination is capitalized if the projects will be further developed or have an alternative future use; otherwise they are expensed. The fair values of IPR&D projects acquired in business combinations are capitalized. Several methods may be used to determine the estimated fair value of the IPR&D acquired in a business combination. The Company utilizes the “income method,” and uses estimated future net cash flows that are derived from projected sales revenues and estimated costs. These projections are based on factors such as relevant market size, patent protection, historical pricing and expected industry trends. The estimated future net cash flows are then discounted to the present value using an appropriate discount rate. These assets are treated as indefinite-lived intangible assets until completion or abandonment of the projects, at which time the assets are amortized over the remaining useful life or written off, as appropriate. IPR&D intangible assets which are determined to have had a drop in their fair value are adjusted downward and an expense recognized on the statement of operations. These are tested at least annually or sooner when a triggering event occurs that could indicate a potential impairment.
	Collaborations
	The Company recognizes collaboration revenues and expenses by analyzing each element of the agreement to determine if it shall be accounted for as a separate element or single unit of accounting. If an element shall be treated separately for revenue recognition purposes, the revenue recognition principles most appropriate for that element are applied to determine when revenue shall be recognized. If an element shall not be treated separately for revenue recognition purposes, the revenue recognition principles most appropriate for the bundled group of elements are applied to determine when revenue shall be recognized. Payments received in excess of revenues recognized are recorded as deferred revenue until such time as the revenue recognition criteria have been met.
	Concentration of Credit Risk
	The Company’s principal direct customers as of June 30, 2014 were a network of specialty pharmacies, Kaiser Permanente, and the specialty distributor to the VA for Ampyra, wholesale pharmaceutical distributors for Zanaflex Capsules and Zanaflex tablets, and two specialty distributors for Qutenza. The Company periodically assesses the financial strength of these customers and establishes allowances for anticipated losses, if necessary. Four customers individually accounted for more than 10% of the Company’s product revenue in 2014 and 2013. Four and three customers individually accounted for more than 10% of the Company’s accounts receivable as of June 30, 2014 and December 31, 2013, respectively. The Company’s net product revenues are generated in the United States.
	Segment and Geographic Information
	The Company is managed and operated as one business which is focused on the identification, development and commercialization of novel therapies that improve neurological function in people with MS, SCI and other disorders of the central nervous system. The entire business is managed by a single management team that reports to the Chief Executive Officer. The Company does not operate separate lines of business with respect to any of its products or product candidates and the Company does not prepare discrete financial information with respect to separate products or product candidates or by location.  Accordingly, the Company views its business as one reportable operating segment. Net product revenues reported to date are derived from the sales of Ampyra, Zanaflex and Qutenza in the United States.
	Subsequent Events
	Subsequent events are defined as those events or transactions that occur after the balance sheet date, but before the financial statements are filed with the Securities and Exchange Commission. The Company completed an evaluation of the impact of any subsequent events through the date these financial statements were issued, and determined there were no subsequent events requiring disclosure in or requiring adjustment to these financial statements.
	Recent Accounting Pronouncements
	In July 2013, the FASB issued Accounting Standards Update “Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists” (ASU 2013-11). ASU 2013-11 requires an entity to present an unrecognized tax benefit as a reduction of a deferred tax asset for a net operating loss (NOL) carryforward, or similar tax loss or tax credit carryforward, rather than as a liability when (1) the uncertain tax position would reduce the NOL or other carryforward under the tax law of the applicable jurisdiction and (2) the entity intends to use the deferred tax asset for that purpose. ASU 2013-11 is effective prospectively for fiscal years and interim periods within those years, beginning after December 15, 2013 for public entities. The adoption of ASU 2013-11 did not have a significant impact on the Company’s consolidated financial statements.
	In May 2014, the FASB issued Accounting Standards Update 2014-09, “Revenue from Contracts with Customers” (ASU 2014-09), which requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services.  The new guidance also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract.  ASU 2014-09 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016.  The Company is currently evaluating the impact of the new standard.

Sharebased_Compensation

Share-based Compensation	6 Months Ended
	Jun. 30, 2014
Share-based Compensation	'
Share-based Compensation	'
	(3) Share-based Compensation
	During the three-month periods ended June 30, 2014 and 2013, the Company recognized share-based compensation expense of $7.6 million and $6.5 million, respectively. During the six-month periods ended June 30, 2014 and 2013, the Company recognized share-based compensation expense of $13.4 million and $11.5 million, respectively. Activity in options and restricted stock during the six-month period ended June 30, 2014 and related balances outstanding as of that date are reflected below. The weighted average fair value per share of options granted to employees for the three-month periods ended June 30, 2014 and 2013 were approximately $15.37 and $16.81, respectively. The weighted average fair value per share of options granted to employees for the six-month periods ended June 30, 2014 and 2013 were approximately $18.18 and $15.56, respectively.
	The following table summarizes share-based compensation expense included within the consolidated statements of operations:
		For the three-month						For the six-month
		period ended June 30,						period ended June 30,
	(In millions)	2014			2013			2014			2013
	Research and development	$	1.6		$	1.5		$	2.7		$	2.7
	Selling, general and administrative	6			5			10.7			8.8
	Total	$	7.6		$	6.5		$	13.4		$	11.5
	A summary of share-based compensation activity for the six-month period ended June 30, 2014 is presented below:
	Stock Option Activity
		Number of Shares		Weighted Average			Weighted Average		Intrinsic Value
		(In thousands)		Exercise Price			Remaining		(In thousands)
							Contractual
							Term
	Balance at January 1, 2014	6,486		$	25.61
	Granted	1,625		37.31
	Cancelled	(129	)	31.31
	Exercised	(173	)	25.35
	Balance at June 30, 2014	7,809		$	27.96		7		$	52,648
	Vested and expected to vest at June 30, 2014	7,709		$	27.87		6.9		$	52,477
	Vested and exercisable at June 30, 2014	4,378		$	24.16		5.4		$	42,555
	Restricted Stock Activity
	(In thousands)	Number of Shares
	Restricted Stock
	Nonvested at January 1, 2014	421
	Granted	284
	Vested	(4	)
	Forfeited	(20	)
	Nonvested at June 30, 2014	681
	Unrecognized compensation cost for unvested stock options and restricted stock awards as of June 30, 2014 totaled $67.9 million and is expected to be recognized over a weighted average period of approximately 2.8 years.

Earnings_Per_Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2014
Earnings Per Share	'
Earnings Per Share	'
	(4) Earnings Per Share
	The following table sets forth the computation of basic and diluted earnings per share for the three and six-month periods ended June 30, 2014 and 2013:
	(In thousands, except per share data)	Three-month			Three-month		Six-month		Six-month
		period ended			period ended		period ended		period ended
		June 30, 2014			June 30, 2013		June 30, 2014		June 30, 2013
	Basic and diluted
	Net income	$	4,685		$	3,910	$	5,390	$	2,772
	Weighted average common shares outstanding used in computing net income per share—basic	41,032			39,960		40,985		39,896
	Plus: net effect of dilutive stock options and restricted common shares	1,400			1,623		1,351		1,415
	Weighted average common shares outstanding used in computing net income per share—diluted	42,432			41,583		42,336		41,311
	Net income per share—basic	$	0.11		$	0.1	$	0.13	$	0.07
	Net income per share—diluted	$	0.11		$	0.09	$	0.13	$	0.07
	The difference between basic and diluted shares is that diluted shares include the dilutive effect of the assumed exercise of outstanding securities. The Company’s stock options and unvested shares of restricted common stock could have the most significant impact on diluted shares.
	Securities that could potentially be dilutive are excluded from the computation of diluted earnings per share when a loss from continuing operations exists or when the exercise price exceeds the average closing price of the Company’s common stock during the period, because their inclusion would result in an anti-dilutive effect on per share amounts.
	In June 2014, the Company issued $345 million aggregate principal amount of 1.75% Convertible Senior Notes (the “Notes”), which aggregate principal amount includes the exercise of the underwriter’s over-allotment option.  See Note 8 — “Convertible Senior Notes”.  As the Company has a choice to settle the conversion obligation under the Notes in cash, shares or any combination of the two, the Company has determined that it intends to and has the ability to settle the accreted principal value of the Notes in cash and the excess conversion premium in shares. While the dilutive effect of the potential conversion premium will be considered in the calculation of diluted net income per share using the treasury stock method, the accreted principal value of the Notes will not be included in the calculation of diluted income per share, as we intend to settle this in cash.
	The following amounts were not included in the calculation of net income per diluted share because their effects were anti-dilutive:
	(In thousands)	Three-month		Three-month		Six-month	Six-month
		period ended		period ended		period ended	period ended
		June 30, 2014		June 30, 2013		June 30, 2014	June 30, 2013
	Denominator
	Stock options and restricted common shares	3,739		1,762		3,859	3,139
	Convertible note — Saints Capital	29		39		29	39

Income_Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2014
Income Taxes	'
Income Taxes	'
	(5) Income Taxes
	For the six-month periods ended June 30, 2014 and 2013, the Company recorded a provision for income taxes of $8.8 million and $2.5 million, respectively, based upon its estimated tax liability for the year. The provision for/benefit from income taxes is based on federal, state and Puerto Rico income taxes. The effective income tax rates for the Company for the three-month periods ended June 30, 2014 and 2013 were 56% and 52%, respectively.  The effective income tax rates for the Company for the six-month periods ended June 30, 2014 and 2013 were 62% and 47%, respectively.  As a result of the Federal research and development tax credit not being extended during the first and second quarter of 2014, the Company was not able to receive a benefit in the effective tax rate for this in 2014.
	The Company continues to evaluate the realizability of its deferred tax assets and liabilities on a periodic basis and will adjust such amounts in light of changing facts and circumstances including, but not limited to, future projections of taxable income, tax legislation, rulings by relevant tax authorities, the progress of ongoing tax audits and the regulatory approval of products currently under development. Any changes to the valuation allowance or deferred tax assets in the future would impact the Company’s income taxes.

Fair_Value_Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2014
Fair Value Measurements	'
Fair Value Measurements	'
	(6) Fair Value Measurements
	The following table presents information about the Company’s assets and liabilities measured at fair value on a recurring basis as of June 30, 2014 and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value. In general, fair values determined by Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities. Fair values determined by Level 2 inputs utilize data points that are observable, such as quoted prices, interest rates and yield curves. Fair values determined by Level 3 inputs utilize unobservable data points for the asset or liability. The Company’s Level 1 assets consist of time deposits and investments in a Treasury money market fund and the Company’s Level 2 assets consist of high-quality government bonds and are valued using market prices on the active markets.  Level 1 instrument valuations are obtained from real-time quotes for transactions in active exchange markets involving identical assets and Level 2 assets are valued using quoted prices for similar assets and liabilities in active markets or other market observable inputs such as interest rates and yield curves. The Company’s Level 3 liabilities represent our put/call liability related to the Paul Royalty Fund (PRF) transaction and contingent consideration related to the NeurogesX acquisition. No changes in valuation techniques or inputs occurred during the three or six months ended June 30, 2014.
	(In thousands)	Level 1		Level 2			Level 3
	June 30, 2014
	Assets Carried at Fair Value:
	Cash equivalents	$	253,604	$	—		$	—
	Short-term investments	—		331,254			—
	Long-term investments	—		121,855			—
	Liabilities Carried at Fair Value:
	Put/call liability	—		—			167
	Contingent purchase price	—		—			254
	December 31, 2013
	Assets Carried at Fair Value:
	Cash equivalents	$	28,308	$	—		$	—
	Short-term investments	—		225,891			—
	Long-term investments	—		93,299			—
	Liabilities Carried at Fair Value:
	Put/call liability	—		—			147
	Contingent purchase price	—		—			236
	The following tables present additional information about assets and/or liabilities measured at fair value on a recurring basis and for which the Company utilizes Level 3 inputs to determine fair value.
	Put/call liability
	(In thousands)	Three-month		Three-month			Six-month		Six-month
		period ended		period ended			period ended		period ended
		June 30, 2014		June 30, 2013			June 30, 2014		June 30, 2013
	Put/call liability:
	Balance, beginning of period	$	167	$	247		$	147	$	329
	Total realized and unrealized gains included in selling, general and administrative expenses:	—		(247		)	20		(329		)
	Balance, end of period	$	167	$	—		$	167	$	—
	The Company estimates the fair value of its put/call liability using a discounted cash flow valuation technique. Using this approach, historical and expected future cash flows are calculated over the expected life of the PRF agreement, are discounted, and then exercise scenario probabilities are applied. Some of the more significant assumptions made in the valuation include (i) the estimated Zanaflex revenue forecast and (ii) the likelihood of put/call exercise trigger events such as bankruptcy and change of control. The valuation is performed periodically when the significant assumptions change.  Realized gains and losses are included in selling, general and administrative expenses.
	The put/call liability has been classified as a Level 3 liability as its valuation requires substantial judgment and estimation of factors that are not currently observable in the market due to the lack of trading in the security. If different assumptions were used for the various inputs to the valuation approach including, but not limited to, assumptions involving the estimated Zanaflex revenue forecast and the likelihood of trigger events, the estimated fair value could be significantly higher or lower than the fair value we determined. The Company may be required to record losses in future periods, which may be significant.
	Contingent purchase price
	(In thousands)	Three-month		Three-month			Six-month		Six-month
		period ended		period ended			period ended		period ended
		June 30, 2014		June 30, 2013			June 30, 2014		June 30, 2013
	Contingent purchase price:
	Balance, beginning of period	$	245	$	—		$	236	$	—
	Total losses included in selling, general and administrative expenses:	9		—			18		—
	Balance, end of period	$	254	$	—		$	254	$	—
	The Company measures the fair value of the contingent purchase price using a Monte Carlo simulation. Using this approach, the present value of each of the milestone payments is calculated using the probability of milestone achievement under various different scenarios. Some of the more significant assumptions used in the valuation include (i) the probability of FDA approval for NP-1998 and (ii) the variability in net sales for NP-1998 if FDA approval is achieved. The milestone achievement probabilities range from 0% to 10%, and the milestone payment outcomes range from $0 to $5.0 million. The valuation will be performed periodically when the significant assumptions change.  Realized gains and losses are included in selling, general and administrative expenses. There is no assurance that any of the conditions for the milestone payments will be met.
	The contingent purchase price has been classified as a Level 3 liability as its valuation requires substantial judgment and estimation of factors that are not currently observable in the market. If different assumptions were used for the various inputs to the valuation approach including, but not limited to, assumptions involving the probability of FDA approval for NP-1998 and the likelihood of trigger events, the estimated fair value could be significantly higher or lower than the fair value we determined. The Company may be required to record losses in future periods.

Investments

Investments	6 Months Ended
	Jun. 30, 2014
Investments	'
Investments	'
	(7) Investments
	The Company has determined that all of its investments are classified as available-for-sale. Available-for-sale securities are carried at fair value with interest on these securities included in interest income and are recorded based primarily on quoted market prices. Available-for-sale securities consisted of the following:
	(In thousands)	Amortized		Gross		Gross			Estimated
		Cost		unrealized		unrealized			fair
				gains		losses			value
	June 30, 2014
	US Treasury bonds	$	452,947	$	166	$	(4	)	$	453,109
	December 31, 2013
	US Treasury bonds	319,123		69		(2		)	319,190
	The contractual maturities of short-term available-for-sale debt securities at June 30, 2014 and December 31, 2013 are greater than 3 months but less than 1 year. The contractual and intended maturities of long-term available-for-sale debt securities at June 30, 2014 and December 31, 2013 are greater than 1 year and up to 16 months. The Company has determined that there were no other-than-temporary declines in the fair values of its investments as of June 30, 2014.
	Short-term investments with maturity of three months or less from date of purchase have been classified as cash equivalents, and amounted to $253.6 million and $28.3 million as of June 30, 2014 and December 31, 2013, respectively.
	The Company holds available-for-sale investment securities which are reported at fair value on the Company’s balance sheet. Unrealized holding gains and losses are reported within accumulated other comprehensive income (AOCI) in the statements of comprehensive (loss) income.  The changes in AOCI associated with the unrealized holding gain on available-for-sale investments during the six months ended June 30, 2014, were as follows (in thousands):
	(In thousands)	Net Unrealized
		Gains on
		Marketable
		Securities, Net of
		Tax
	Balance at December 31, 2013	$	37
	Other comprehensive income before reclassifications:	59
	Amounts reclassified from accumulated other comprehensive income	—
	Net current period other comprehensive income	59
	Balance at June 30, 2014	$	96

Convertible_Senior_Notes

Convertible Senior Notes	6 Months Ended
	Jun. 30, 2014
Convertible Senior Notes	'
Convertible Senior Notes	'
	(8) Convertible Senior Notes
	On June 17, 2014, the Company entered into an underwriting agreement (the “Underwriting Agreement”) with J.P. Morgan Securities LLC (the “Underwriter”) relating to the issuance by the Company of $345 million aggregate principal amount of 1.75% Convertible Senior Notes due 2021 (the “Notes”) in an underwritten public offering pursuant to the Company’s Registration Statement on Form S-3 (File No. 333-196803) (the “Registration Statement”) and a related preliminary and final prospectus supplement, filed with the Securities and Exchange Commission (the “Offering”). The principal amount of Notes includes $45 million aggregate principal amount of Notes that was purchased by the Underwriter pursuant to an option granted to the Underwriter in the Underwriting Agreement, which option was exercised in full. The net proceeds from the offering, after deducting the Underwriter’s discount and the estimated offering expenses payable by the Company, were approximately $337.6 million.
	The Notes are governed by the terms of an indenture, dated as of June 23, 2014 (the “Base Indenture”) and the first supplemental indenture, dated as of June 23, 2014 (the “Supplemental Indenture,” and together with the Base Indenture, the “Indenture”), each between the Company and Wilmington Trust, National Association, as trustee (the Trustee). The Notes will be convertible into cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock, at the Company’s election, based on an initial conversion rate, subject to adjustment, of 23.4968 shares per $1,000 principal amount of Notes (which represents an initial conversion price of approximately $42.56 per share), only in the following circumstances and to the following extent: (1) during the five business day period after any five consecutive trading day period (the “measurement period”) in which the trading price per $1,000 principal amount of Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; (2) during any calendar quarter commencing after the calendar quarter ending on September 30, 2014 (and only during such calendar quarter), if the last reported sale price of the common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (3) if the Company calls any or all of the Notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date; (4) upon the occurrence of specified events described in the Indenture; and (5) at any time on or after December 15, 2020 through the second scheduled trading day immediately preceding the maturity date.
	The Company may not redeem the Notes prior to June 20, 2017. The Company may redeem for cash all or part of the Notes, at the Company’s option, on or after June 20, 2017 if the last reported sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending within five trading days prior to the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date.
	The Company will pay 1.75% interest per annum on the principal amount of the Notes, payable semiannually in arrears in cash on June 15 and December 15 of each year, beginning on December 15, 2014. The Notes will mature on June 15, 2021.
	If the Company undergoes a “fundamental change” (as defined in the Indenture), subject to certain conditions, holders may require the Company to repurchase for cash all or part of their Notes in principal amounts of $1,000 or an integral multiple thereof. The fundamental change repurchase price will be equal to 100% of the principal amount of the Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. If a make-whole fundamental change, as described in the Indenture, occurs and a holder elects to convert its Notes in connection with such make-whole fundamental change, such holder may be entitled to an increase in the conversion rate as described in the Indenture.
	The Indenture contains customary terms and covenants and events of default. If an event of default (other than certain events of bankruptcy, insolvency or reorganization involving the Company) occurs and is continuing, the Trustee by notice to the Company, or the holders of at least 25% in principal amount of the outstanding Notes by notice to the Company and the Trustee, may declare 100% of the principal of and accrued and unpaid interest, if any, on all the Notes to be due and payable. Upon such a declaration of acceleration, such principal and accrued and unpaid interest, if any, will be due and payable immediately. Upon the occurrence of certain events of bankruptcy, insolvency or reorganization involving the Company, 100% of the principal of and accrued and unpaid interest, if any, on all of the Notes will become due and payable automatically. Notwithstanding the foregoing, the Indenture provides that, to the extent the Company elects and for up to 270 days, the sole remedy for an event of default relating to certain failures by the Company to comply with certain reporting covenants in the Indenture consists exclusively of the right to receive additional interest on the Notes.
	The Notes will be senior unsecured obligations and will rank equally with all of the Company’s existing and future senior debt and senior to any of the Company’s subordinated debt. The Notes will be structurally subordinated to all existing or future indebtedness and other liabilities (including trade payables) of the Company’s subsidiaries and will be effectively subordinated to the Company’s existing or future secured indebtedness to the extent of the value of the collateral. The Indenture does not limit the amount of debt that the Company or its subsidiaries may incur.
	In accounting for the issuance of the Notes, the Company separated the Notes into liability and equity components. The carrying amount of the liability component was calculated by measuring the fair value of a similar liability that does not have an associated convertible feature. The carrying amount of the equity component representing the conversion option was determined by deducting the fair value of the liability component from the par value of the Notes as a whole. The excess of the principal amount of the liability component over its carrying amount, referred to as the debt discount, is amortized to interest expense over the seven-year term of the Notes using the effective interest method. The equity component is not re-measured as long as it continues to meet the conditions for equity classification.
	Our outstanding note balances as of June 30, 2014 consisted of the following:
	(In thousands)	June 30, 2014
	Liability component:
	Principal	$	345,000
	Less: debt discount, net	(61,052		)
	Net carrying amount	$	283,948
	Equity component	$	61,195
	In connection with the issuance of the Notes, we incurred approximately $7.4 million of debt issuance costs, which primarily consisted of underwriting, legal and other professional fees, and allocated these costs to the liability and equity components based on the allocation of the proceeds. Of the total $7.4 million of debt issuance costs, $1.2 million were allocated to the equity component and recorded as a reduction to additional paid-in capital and $6.2 million were allocated to the liability component and recorded as deferred financing costs included in other assets on the balance sheet. The portion allocated to the liability component is amortized to interest expense over the expected life of the Notes using the effective interest method.
	We determined the expected life of the debt was equal to the seven year term on the Notes. The carrying amount of the Company’s borrowings of $283.9 million approximates fair value at June 30, 2014. As of June 30, 2014, the remaining contractual life of the Notes is approximately 7.0 years. The effective interest rate on the liability component was 4.8% for the period from the date of issuance through June 30, 2014. The following table sets forth total interest expense recognized related to the Notes during the three months ended June 30, 2014:
	(In thousands)	June 30, 2014
	Contractual interest expense	$	116
	Amortization of debt issuance costs	14
	Amortization of debt discount	143
	Total interest expense	$	273

Collaborations_Alliances_and_O

Collaborations, Alliances, and Other Agreements	6 Months Ended
	Jun. 30, 2014
Collaborations, Alliances, and Other Agreements	'
Collaborations, Alliances, and Other Agreements	'
	(9) Collaborations, Alliances, and Other Agreements
	Biogen
	On June 30, 2009, the Company entered into an exclusive collaboration and license agreement with Biogen Idec International GmbH (Biogen Idec) to develop and commercialize Ampyra (known as Fampyra outside the U.S.) in markets outside the United States (the “Collaboration Agreement”). Under the Collaboration Agreement, Biogen Idec was granted the exclusive right to commercialize Ampyra and other products containing aminopyridines developed under that agreement in all countries outside of the United States, which grant includes a sublicense of the Company’s rights under an existing license agreement between the Company and Alkermes plc (Alkermes), formerly Elan Corporation, plc (Elan). Biogen Idec has responsibility for regulatory activities and future clinical development of Fampyra in ex-U.S. markets worldwide. The Company also entered into a related supply agreement with Biogen Idec (the “Supply Agreement”), pursuant to which the Company will supply Biogen Idec with its requirements for the licensed products through the Company’s existing supply agreement with Alkermes.
	Under the Collaboration Agreement, the Company was entitled to an upfront payment of $110.0 million as of June 30, 2009, which was received in July 2009, and a $25.0 million milestone payment upon approval of the product in the European Union, which was received in August 2011. The Company is also entitled to receive additional payments of up to $10.0 million based on the successful achievement of future regulatory milestones and up to $365.0 million based on the successful achievement of future sales milestones. Due to the uncertainty surrounding the achievement of the future regulatory and sales milestones, these payments will not be recognized as revenue unless and until they are earned. The Company is not able to reasonably predict if and when the milestones will be achieved. Under the Collaboration Agreement, Biogen Idec will be required to make double-digit tiered royalty payments to the Company on ex-U.S. sales. In addition, the consideration that Biogen Idec will pay for licensed products under the Supply Agreement will reflect the price owed to the Company’s suppliers under its supply arrangements with Alkermes or other suppliers for ex-U.S. sales. The Company and Biogen Idec may also carry out future joint development activities regarding licensed product under a cost-sharing arrangement. Under the terms of the Collaboration Agreement, the Company, in part through its participation in joint committees with Biogen Idec, will participate in overseeing the development and commercialization of Ampyra and other licensed products in markets outside the United States pursuant to that agreement. Acorda will continue to develop and commercialize Ampyra independently in the United States.
	As of June 30, 2009, the Company recorded a license receivable and deferred revenue of $110.0 million for the upfront payment due to the Company from Biogen Idec under the Collaboration Agreement. Also, as a result of such payment to Acorda, a payment of $7.7 million became payable by Acorda to Alkermes and was recorded as a cost of license payable and deferred expense. The payment of $110.0 million was received from Biogen Idec on July 1, 2009 and the payment of $7.7 million was made to Alkermes on July 7, 2009.
	The Company considered the following deliverables with respect to the revenue recognition of the $110.0 million upfront payment:  (1) the license to use the Company’s technology, (2) the Collaboration Agreement to develop and commercialize licensed product in all countries outside the U.S., and (3) the Supply Agreement. Due to the inherent uncertainty in obtaining regulatory approval, the applicability of the Supply Agreement is outside the control of the Company and Biogen Idec. Accordingly, the Company has determined the Supply Agreement is a contingent deliverable at the onset of the agreement.  As a result, the Company has determined the Supply Agreement does not meet the definition of a deliverable that needs to be accounted for at the inception of the arrangement. The Company has also determined that there is no significant and incremental discount related to the supply agreement since Biogen Idec will pay the same amount for inventory that the Company would pay and the Company effectively acts as a middle man in the arrangement for which it adds no significant value due to various factors such as the Company does not have any manufacturing capabilities or other know how with respect to the manufacturing process.
	The Company has determined that the identified non-contingent deliverables (deliverables 1 and 2 immediately preceding) would have no value on a standalone basis if they were sold separately by a vendor and the customer could not resell the delivered items on a standalone basis, nor does the Company have objective and reliable evidence of fair value for the deliverables. Accordingly, the non-contingent deliverables are treated as one unit of accounting.  As a result, the Company will recognize the non-refundable upfront payment from Biogen Idec as revenue and the associated payment to Alkermes as expense ratably over the estimated term of regulatory exclusivity for the licensed products under the Collaboration Agreement as the Company had determined this was the most probable expected benefit period. The Company recognized $2.3 million and $4.5 million in license revenue, a portion of the $110.0 million received from Biogen Idec, and $159,000 and $317,000 in cost of license revenue, a portion of the $7.7 million paid to Alkermes, during the three and six-month periods ended June 30, 2014 and 2013, respectively.
	On January 21, 2011 Biogen Idec announced that the European Medicines Agency’s (EMA) Committee for Medicinal Products for Human Use (CHMP) decided against approval of Fampyra to improve walking ability in adult patients with multiple sclerosis.  Biogen Idec, working closely with the Company, filed a formal appeal of the decision.  In May 2011, the CHMP recommended conditional marketing authorization, and in July 2011 Biogen Idec received conditional approval from the European Commission for, Fampyra (prolonged-release fampridine tablets) for the improvement of walking in adult patients with MS with walking disability (Expanded Disability Status Scale of 4-7). The Company currently estimates the recognition period to be approximately 12 years from the date of the Collaboration Agreement. As part of its ex-U.S. license agreement, Biogen Idec owes Acorda royalties based on ex-U.S. net sales, and milestones based on ex-U.S. regulatory approval, new indications, and ex-U.S. net sales.  These milestones included a $25.0 million payment for approval of the product in the European Union which was recorded and paid in the three month period ended September 30, 2011. Based on Acorda’s worldwide license and supply agreement with Alkermes, Alkermes received 7% of this milestone payment from Acorda during the same period.  For revenue recognition purposes, the Company determined this milestone to be substantive in accordance with applicable accounting guidance related to milestone revenue.  Substantive uncertainty existed at the inception of the arrangement as to whether the milestone would be achieved because of the numerous variables, such as the high rate of failure inherent in the research and development of new products and the uncertainty involved with obtaining regulatory approval. Biogen Idec leveraged Acorda’s U.S. Ampyra study results that contributed to the regulatory approval process. Therefore, the milestone was achieved based in part on Acorda’s past performance.  The milestone was also reasonable relative to all deliverable and payment terms of the collaboration arrangement. Therefore, the payment was recognized in its entirety as revenue and the cost of the milestone revenue was recognized in its entirety as an expense during the three-month period ended September 30, 2011.
	Actavis/Watson
	The Company has an agreement with Watson Pharma, Inc., a subsidiary of Actavis, Inc. (formerly Watson Pharmaceuticals, Inc.), to market tizanidine hydrochloride capsules, an authorized generic version of Zanaflex Capsules which was launched in February 2012.  In accordance with the Watson agreement, the Company receives a royalty based on Watson’s gross margin, as defined by the agreement, of the authorized generic product. During the three-month periods ended June 30, 2014 and 2013, the Company recognized royalty revenue of $2.4 million and $2.5 million, respectively, related to the gross margin of the Zanaflex Capsule authorized generic.  During the three-month periods ended June 30, 2014 and 2013, the Company also recognized revenue and a corresponding cost of sales of $1.3 million and $1.1 million, respectively, related to the purchase and sale of the related Zanaflex Capsule authorized generic product to Watson, which is recorded in net product revenues and cost of sales.
	During the six-month periods ended June 30, 2014 and 2013, the Company recognized royalty revenue of $3.8 million and $5.1 million, respectively, related to the gross margin of the Zanaflex Capsule authorized generic.  During the six-month periods ended June 30, 2014 and 2013, the Company also recognized revenue and a corresponding cost of sales of $2.2 million and $1.6 million, respectively, related to the purchase and sale of the related Zanaflex Capsule authorized generic product to Watson, which is recorded in net product revenues and cost of sales.
	Neuronex
	In December 2012, the Company acquired Neuronex, Inc., a privately-held development stage pharmaceutical company (Neuronex) developing Plumiaz (our trade name for Diazepam Nasal Spray).  Plumiaz is a proprietary nasal spray formulation of diazepam that we are developing under Section 505(b)(2) of the Food, Drug and Cosmetic Act as an acute treatment for selected, refractory patients with epilepsy, on stable regimens of antiepileptic drugs, or AEDs, who experience intermittent bouts of increased seizure activity also known as cluster seizures or acute repetitive seizures, or ARS.
	Under the terms of the agreement, the Company made an upfront payment of $2.0 million in February 2012.  The Company also paid $1.5 million during the twelve month period ended December 31, 2012 pursuant to a commitment under the agreement to fund research to prepare for the Plumiaz pre-NDA meeting with the FDA.  In December 2012, the Company completed the acquisition by paying $6.8 million to former Neuronex shareholders less a $300,000 holdback provision.  After adjustment for Neuronex’s working capital upon closing of the acquisition, approximately $120,000 of the holdback amount was remaining as of December 31, 2013.  This balance was paid to the former equity holders of Neuronex pursuant to the merger agreement in February 2014.
	The former equity holders of Neuronex are entitled to receive from Acorda up to an additional $18 million in contingent earnout payments upon the achievement of specified regulatory and manufacturing-related milestones with respect to Diazepam Nasal Spray products, and up to $105 million upon the achievement of specified sales milestones with respect to Diazepam Nasal Spray products.  The former equity holders of Neuronex will also be entitled to receive tiered royalty-like earnout payments, ranging from the upper single digits to lower double digits, on worldwide net sales of Diazepam Nasal Spray products.  These payments are payable on a country-by-country basis until the earlier to occur of ten years after the first commercial sale of a product in such country and the entry of generic competition in such country as defined in the Agreement.
	The patent and other intellectual property and other rights relating to Diazepam Nasal Spray products are licensed from SK Biopharmaceuticals Co., Ltd. (SK).  Pursuant to the SK license, which granted worldwide rights to Neuronex, except certain specified Asian countries, the Company’s subsidiary Neuronex is obligated to pay SK up to $8 million upon the achievement of specified development milestones with respect to the Diazepam Nasal Spray product (including a $1 million payment that was triggered during the three-month period ending September 30, 2013 upon the FDA’s acceptance for review of the first NDA for Plumiaz and paid during the three-month period ending December 31, 2013), and up to $3 million upon the achievement of specified sales milestones with respect to the Diazepam Nasal Spray product.  Also, Neuronex is obligated to pay SK a tiered, mid-single digit royalty on net sales of Diazepam Nasal Spray products.
	The Company evaluated the transaction based upon the guidance of ASC 805, Business Combinations, and concluded that it only acquired inputs and did not acquire any processes.  The Company needed to develop its own processes in order to produce an output. Therefore the Company accounted for the transaction as an asset acquisition and accordingly the $2.0 million upfront payment, $1.5 million in research funding and $6.8 million of closing consideration net of tangible net assets acquired of $3.7 million which were primarily the taxable amount of net operating loss carryforwards, were expensed as research and development expense during the twelve-month period ended December 31, 2012.

Commitments_and_Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2014
Commitments and Contingencies	'
Commitments and Contingencies	'
	(10) Commitments and Contingencies
	A summary of the Company’s commitments and contingencies was included in the Company’s Annual Report on Form 10-K for the twelve-month period ended December 31, 2013. The Company’s long-term contractual obligations include commitments and estimated purchase obligations entered into in the normal course of business.
	In May 2014, we exercised our option to lease an additional 25,405 square feet of office space in Ardsley, New York under our current lease agreement with our landlord.  We anticipate occupying the new space during the three-month period ended December 31, 2014, subject to completion of certain improvements to the space prior to our occupancy.
	In June 2014, we issued $345 million aggregate principal amount of 1.75% Convertible Senior Notes (the “Notes”), which aggregate principal amount includes the exercise of the underwriter’s over-allotment option.  The Notes bear interest at the rate of 1.75% per annum, payable semiannually in arrears in cash on June 15 and December 15 of each year, beginning on December 15, 2014. The Notes are due on June 15, 2021, although they can be converted into cash and shares of our common stock prior to maturity if certain conditions are met.  Any conversion prior to maturity can result in repayment of the principal amount sooner than the scheduled repayment. See Note 8 — “Convertible Senior Notes”.
	The Company accrues for amounts related to legal matters if it is probable that a liability has been incurred and the amount is reasonably estimable. While losses, if any, are possible, the Company is not able to estimate any ranges of losses as of June 30, 2014. Litigation expenses are expensed as incurred.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2014
Summary of Significant Accounting Policies	'
Principles of Consolidation	'
	Principles of Consolidation
	The accompanying consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States of America and include the results of operations of the Company and its majority owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation.
Use of Estimates	'
	Use of Estimates
	The preparation of the consolidated financial statements requires management of the Company to make a number of estimates and assumptions relating to the reported amount of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the period. Significant items subject to such estimates and assumptions include share-based compensation accounting, which are largely dependent on the fair value of the Company’s equity securities. In addition, the Company recognizes Zanaflex revenue based on estimated prescriptions filled. The Company adjusts its Zanaflex inventory value based on an estimate of inventory that may be returned. Actual results could differ from those estimates.
Investments	'
	Investments
	Both short-term and long-term investments consist of US Treasury bonds. The Company classifies marketable securities available to fund current operations as short-term investments in current assets on its consolidated balance sheets. Marketable securities are classified as long-term investments in long-term assets on the consolidated balance sheets if the Company has the ability and intent to hold them and such holding period is longer than one year. The Company classifies its short-term and long-term investments as available-for-sale. Available-for-sale securities are recorded at fair value of the investments based on quoted market prices.
	Unrealized holding gains and losses on available-for-sale securities, which are determined to be temporary, are excluded from earnings and are reported as a separate component of accumulated other comprehensive income (loss).
	Premiums and discounts on investments are amortized over the life of the related available-for-sale security as an adjustment to yield using the effective-interest method. Dividend and interest income are recognized when earned. Amortized premiums and discounts, dividend and interest income and realized gains and losses are included in interest income.
Accumulated Other Comprehensive Income	'
	Accumulated Other Comprehensive Income
	The Company’s accumulated other comprehensive income is comprised of gains and losses on available for sale securities and is recorded and presented net of income tax.
Revenue Recognition	'
	Revenue Recognition
	Ampyra
	Ampyra is available only through a network of specialty pharmacy providers that provide the medication to patients by mail; Kaiser Permanente, which distributes Ampyra to patients through a closed network of on-site pharmacies; and ASD Specialty Healthcare, Inc. (an AmerisourceBergen affiliate), which distributes Ampyra to the U.S. Bureau of Prisons and the U.S. Department of Veterans Affairs (VA). Ampyra is not available in retail pharmacies. The Company does not recognize revenue from product sales until there is persuasive evidence of an arrangement, delivery has occurred, the price is fixed and determinable, the buyer is obligated to pay the Company, the obligation to pay is not contingent on resale of the product, the buyer has economic substance apart from the Company, the Company has no obligation to bring about the sale of the product, the amount of returns can be reasonably estimated and collectability is reasonably assured. The Company recognizes product sales of Ampyra following shipment of product to a network of specialty pharmacy providers, Kaiser Permanente, and the specialty distributor to the VA. The specialty pharmacy providers, Kaiser Permanente, and the specialty distributor to the VA are contractually obligated to hold no more than an agreed number of days of inventory, ranging from 10 to 30 days.
	The Company’s net revenues represent total revenues less allowances for customer credits, including estimated discounts, rebates, and chargebacks. These allowances are recorded for cash consideration given by a vendor to a customer that is presumed to be a reduction of the selling prices of the vendor’s products or services and, therefore, are characterized as a reduction of revenue. At the time product is shipped to specialty pharmacies, Kaiser Permanente and the specialty distributor to the VA, an adjustment is recorded for estimated discounts, rebates, and chargebacks. These allowances are established by management as its best estimate based on available information and will be adjusted to reflect known changes in the factors that impact such allowances. Allowances for discounts, rebates, returns and chargebacks are established based on the contractual terms with customers, historical trends, communications with customers and the levels of inventory remaining in the distribution channel, as well as expectations about the market for the product and anticipated introduction of competitive products.  Product shipping and handling costs are included in cost of sales.  The Company does not accept returns of Ampyra with the exception of product damages that occur during shipping.
	Zanaflex
	The Company applies the revenue recognition guidance in Accounting Standards Codification (ASC) 605-15-25, which among other criteria requires that future returns can be reasonably estimated in order to recognize revenue. The amount of future tablet returns is uncertain due to generic competition and customer conversion to Zanaflex Capsules. The Company has accumulated some sales history with Zanaflex Capsules; however, due to existing and potential generic competition and customer conversion from Zanaflex tablets to Zanaflex Capsules, we do not believe we can reasonably determine a return rate at this time. As a result, the Company accounts for these product shipments using a deferred revenue recognition model. Under the deferred revenue model, the Company does not recognize revenue upon product shipment. For these product shipments, the Company invoices the wholesaler, records deferred revenue at gross invoice sales price, and classifies the cost basis of the product held by the wholesaler as a component of inventory. The Company recognizes revenue when prescribed to the end-user, on a first-in first-out (FIFO) basis. The Company’s revenue to be recognized is based on (1) the estimated prescription demand, based on pharmacy sales for its products; and (2) the Company’s analysis of third-party information, including third-party market research data. The Company’s estimates are subject to the inherent limitations of estimates that rely on third-party data, as certain third-party information is itself in the form of estimates, and reflect other limitations. The Company’s sales and revenue recognition reflects the Company’s estimates of actual product prescribed to the end-user. The Company expects to be able to apply a more traditional revenue recognition policy such that revenue is recognized following shipment to the customer when it believes it has sufficient data to develop reasonable estimates of expected returns based upon historical returns and greater certainty regarding generic competition.
	The Company’s net revenues represent total revenues less allowances for customer credits, including estimated discounts, rebates, and chargebacks. These allowances are recorded for cash consideration given by a vendor to a customer that is presumed to be a reduction of the selling prices of the vendor’s products or services and, therefore, should be characterized as a reduction of revenue when recognized in the vendor’s statement of operations. Adjustments are recorded for estimated chargebacks, rebates, and discounts. These allowances are established by management as its best estimate based on available information and are adjusted to reflect known changes in the factors that impact such allowances. Allowances for chargebacks, rebates and discounts are established based on the contractual terms with customers, analysis of historical levels of discounts, chargebacks and rebates, communications with customers and the levels of inventory remaining in the distribution channel, as well as expectations about the market for each product and anticipated introduction of competitive products. In addition, the Company records a charge to cost of goods sold for the cost basis of the estimated product returns the Company believes may ultimately be realized at the time of product shipment to wholesalers. The Company has recognized this charge at the date of shipment since it is probable that it will receive a level of returned products; upon the return of such product it will be unable to resell the product considering its expiration dating; and it can reasonably estimate a range of returns. This charge represents the cost basis for the low end of the range of the Company’s estimated returns. Product shipping and handling costs are included in cost of sales.
	Qutenza
	Qutenza is distributed in the United States by Besse Medical, Inc., a specialty distributor that furnishes the medication to physician offices; and by ASD Specialty Healthcare, Inc., a specialty distributor that furnishes the medication to hospitals and clinics. The Company does not recognize revenue from product sales until there is persuasive evidence of an arrangement, delivery has occurred, the price is fixed and determinable, the buyer is obligated to pay the Company, the obligation to pay is not contingent on resale of the product, the buyer has economic substance apart from the Company, the Company has no obligation to bring about the sale of the product, and the amount of returns can be reasonably estimated and collectability is reasonably assured. This means that, for Qutenza, the Company recognizes product sales following shipment of product to its specialty distributors.
	The Company’s net revenues represent total revenues less allowances for customer credits, including estimated rebates, chargebacks, and returns. These allowances are recorded for cash consideration given by a vendor to a customer that is presumed to be a reduction of the selling prices of the vendor’s products or services and, therefore, are characterized as a reduction of revenue. At the time product is shipped, an adjustment is recorded for estimated rebates, chargebacks, and returns. These allowances are established by management as its best estimate based on available information and will be adjusted to reflect known changes in the factors that impact such allowances. Allowances for rebates, chargebacks, and returns are established based on the contractual terms with customers, historical trends, as well as expectations about the market for the product and anticipated introduction of competitive products.  Product shipping and handling costs are included in cost of sales.
	Milestones and royalties
	In order to determine the revenue recognition for contingent milestones, the Company evaluates the contingent milestones using the criteria as provided by the Financial Accounting Standards Boards (FASB) guidance on the milestone method of revenue recognition. At the inception of a collaboration agreement the Company evaluates if payments are substantive.  The criteria requires that (i) the Company determines if the milestone is commensurate with either its performance to achieve the milestone or the enhancement of value resulting from the Company’s activities to achieve the milestone, (ii) the milestone be related to past performance, and (iii) the milestone be reasonable relative to all deliverable and payment terms of the collaboration arrangement.  If these criteria are met then the contingent milestones can be considered substantive milestones and will be recognized as revenue in the period that the milestone is achieved. Royalties are recognized as earned in accordance with the terms of various research and collaboration agreements.
In-Process Research and Development	'
	In-Process Research and Development
	The cost of in-process research and development (IPR&D) acquired directly in a transaction other than a business combination is capitalized if the projects will be further developed or have an alternative future use; otherwise they are expensed. The fair values of IPR&D projects acquired in business combinations are capitalized. Several methods may be used to determine the estimated fair value of the IPR&D acquired in a business combination. The Company utilizes the “income method,” and uses estimated future net cash flows that are derived from projected sales revenues and estimated costs. These projections are based on factors such as relevant market size, patent protection, historical pricing and expected industry trends. The estimated future net cash flows are then discounted to the present value using an appropriate discount rate. These assets are treated as indefinite-lived intangible assets until completion or abandonment of the projects, at which time the assets are amortized over the remaining useful life or written off, as appropriate. IPR&D intangible assets which are determined to have had a drop in their fair value are adjusted downward and an expense recognized on the statement of operations. These are tested at least annually or sooner when a triggering event occurs that could indicate a potential impairment.
Collaborations	'
	Collaborations
	The Company recognizes collaboration revenues and expenses by analyzing each element of the agreement to determine if it shall be accounted for as a separate element or single unit of accounting. If an element shall be treated separately for revenue recognition purposes, the revenue recognition principles most appropriate for that element are applied to determine when revenue shall be recognized. If an element shall not be treated separately for revenue recognition purposes, the revenue recognition principles most appropriate for the bundled group of elements are applied to determine when revenue shall be recognized. Payments received in excess of revenues recognized are recorded as deferred revenue until such time as the revenue recognition criteria have been met.
Concentration of Credit Risk	'
	Concentration of Credit Risk
	The Company’s principal direct customers as of June 30, 2014 were a network of specialty pharmacies, Kaiser Permanente, and the specialty distributor to the VA for Ampyra, wholesale pharmaceutical distributors for Zanaflex Capsules and Zanaflex tablets, and two specialty distributors for Qutenza. The Company periodically assesses the financial strength of these customers and establishes allowances for anticipated losses, if necessary. Four customers individually accounted for more than 10% of the Company’s product revenue in 2014 and 2013. Four and three customers individually accounted for more than 10% of the Company’s accounts receivable as of June 30, 2014 and December 31, 2013, respectively. The Company’s net product revenues are generated in the United States.
Segment and Geographic Information	'
	Segment and Geographic Information
	The Company is managed and operated as one business which is focused on the identification, development and commercialization of novel therapies that improve neurological function in people with MS, SCI and other disorders of the central nervous system. The entire business is managed by a single management team that reports to the Chief Executive Officer. The Company does not operate separate lines of business with respect to any of its products or product candidates and the Company does not prepare discrete financial information with respect to separate products or product candidates or by location.  Accordingly, the Company views its business as one reportable operating segment. Net product revenues reported to date are derived from the sales of Ampyra, Zanaflex and Qutenza in the United States.
Subsequent Events	'
	Subsequent Events
	Subsequent events are defined as those events or transactions that occur after the balance sheet date, but before the financial statements are filed with the Securities and Exchange Commission. The Company completed an evaluation of the impact of any subsequent events through the date these financial statements were issued, and determined there were no subsequent events requiring disclosure in or requiring adjustment to these financial statements.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In July 2013, the FASB issued Accounting Standards Update “Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists” (ASU 2013-11). ASU 2013-11 requires an entity to present an unrecognized tax benefit as a reduction of a deferred tax asset for a net operating loss (NOL) carryforward, or similar tax loss or tax credit carryforward, rather than as a liability when (1) the uncertain tax position would reduce the NOL or other carryforward under the tax law of the applicable jurisdiction and (2) the entity intends to use the deferred tax asset for that purpose. ASU 2013-11 is effective prospectively for fiscal years and interim periods within those years, beginning after December 15, 2013 for public entities. The adoption of ASU 2013-11 did not have a significant impact on the Company’s consolidated financial statements.
	In May 2014, the FASB issued Accounting Standards Update 2014-09, “Revenue from Contracts with Customers” (ASU 2014-09), which requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services.  The new guidance also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and changes in judgments and assets recognized from costs incurred to obtain or fulfill a contract.  ASU 2014-09 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2016.  The Company is currently evaluating the impact of the new standard.

Sharebased_Compensation_Tables

Share-based Compensation (Tables)	6 Months Ended
	Jun. 30, 2014
Share-based Compensation	'
Summary of share-based compensation expense	'
		For the three-month						For the six-month
		period ended June 30,						period ended June 30,
	(In millions)	2014			2013			2014			2013
	Research and development	$	1.6		$	1.5		$	2.7		$	2.7
	Selling, general and administrative	6			5			10.7			8.8
	Total	$	7.6		$	6.5		$	13.4		$	11.5
Summary of stock option activity	'
		Number of Shares		Weighted Average			Weighted Average		Intrinsic Value
		(In thousands)		Exercise Price			Remaining		(In thousands)
							Contractual
							Term
	Balance at January 1, 2014	6,486		$	25.61
	Granted	1,625		37.31
	Cancelled	(129	)	31.31
	Exercised	(173	)	25.35
	Balance at June 30, 2014	7,809		$	27.96		7		$	52,648
	Vested and expected to vest at June 30, 2014	7,709		$	27.87		6.9		$	52,477
	Vested and exercisable at June 30, 2014	4,378		$	24.16		5.4		$	42,555
Summary of restricted stock activity	'
	(In thousands)	Number of Shares
	Restricted Stock
	Nonvested at January 1, 2014	421
	Granted	284
	Vested	(4	)
	Forfeited	(20	)
	Nonvested at June 30, 2014	681

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2014
Earnings Per Share	'
Schedule of computation of basic and diluted earnings per share	'
	(In thousands, except per share data)	Three-month			Three-month		Six-month		Six-month
		period ended			period ended		period ended		period ended
		June 30, 2014			June 30, 2013		June 30, 2014		June 30, 2013
	Basic and diluted
	Net income	$	4,685		$	3,910	$	5,390	$	2,772
	Weighted average common shares outstanding used in computing net income per share—basic	41,032			39,960		40,985		39,896
	Plus: net effect of dilutive stock options and restricted common shares	1,400			1,623		1,351		1,415
	Weighted average common shares outstanding used in computing net income per share—diluted	42,432			41,583		42,336		41,311
	Net income per share—basic	$	0.11		$	0.1	$	0.13	$	0.07
	Net income per share—diluted	$	0.11		$	0.09	$	0.13	$	0.07
Schedule of antidilutive securities excluded from calculation of net income per diluted share	'
	(In thousands)	Three-month		Three-month		Six-month	Six-month
		period ended		period ended		period ended	period ended
		June 30, 2014		June 30, 2013		June 30, 2014	June 30, 2013
	Denominator
	Stock options and restricted common shares	3,739		1,762		3,859	3,139
	Convertible note — Saints Capital	29		39		29	39

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2014
Fair Value Measurements	'
Schedule of assets and liabilities measured at fair value on a recurring basis	'
	(In thousands)	Level 1		Level 2			Level 3
	June 30, 2014
	Assets Carried at Fair Value:
	Cash equivalents	$	253,604	$	—		$	—
	Short-term investments	—		331,254			—
	Long-term investments	—		121,855			—
	Liabilities Carried at Fair Value:
	Put/call liability	—		—			167
	Contingent purchase price	—		—			254
	December 31, 2013
	Assets Carried at Fair Value:
	Cash equivalents	$	28,308	$	—		$	—
	Short-term investments	—		225,891			—
	Long-term investments	—		93,299			—
	Liabilities Carried at Fair Value:
	Put/call liability	—		—			147
	Contingent purchase price	—		—			236
Schedule of assets and/or liabilities measured at fair value on a recurring basis utilizing Level 3 inputs	'
	(In thousands)	Three-month		Three-month			Six-month		Six-month
		period ended		period ended			period ended		period ended
		June 30, 2014		June 30, 2013			June 30, 2014		June 30, 2013
	Put/call liability:
	Balance, beginning of period	$	167	$	247		$	147	$	329
	Total realized and unrealized gains included in selling, general and administrative expenses:	—		(247		)	20		(329		)
	Balance, end of period	$	167	$	—		$	167	$	—
Schedule of contingent purchase price	'
	(In thousands)	Three-month		Three-month			Six-month		Six-month
		period ended		period ended			period ended		period ended
		June 30, 2014		June 30, 2013			June 30, 2014		June 30, 2013
	Contingent purchase price:
	Balance, beginning of period	$	245	$	—		$	236	$	—
	Total losses included in selling, general and administrative expenses:	9		—			18		—
	Balance, end of period	$	254	$	—		$	254	$	—

Investments_Tables

Investments (Tables)	6 Months Ended
	Jun. 30, 2014
Investments	'
Schedule of available-for-sale securities	'
	(In thousands)	Amortized		Gross		Gross			Estimated
		Cost		unrealized		unrealized			fair
				gains		losses			value
	June 30, 2014
	US Treasury bonds	$	452,947	$	166	$	(4	)	$	453,109
	December 31, 2013
	US Treasury bonds	319,123		69		(2		)	319,190
Schedule of changes in accumulated other comprehensive income	'
	(In thousands)	Net Unrealized
		Gains on
		Marketable
		Securities, Net of
		Tax
	Balance at December 31, 2013	$	37
	Other comprehensive income before reclassifications:	59
	Amounts reclassified from accumulated other comprehensive income	—
	Net current period other comprehensive income	59
	Balance at June 30, 2014	$	96

Convertible_Senior_Notes_Table

Convertible Senior Notes (Tables)	6 Months Ended
	Jun. 30, 2014
Convertible Senior Notes	'
Summary of outstanding note	'
	(In thousands)	June 30, 2014
	Liability component:
	Principal	$	345,000
	Less: debt discount, net	(61,052		)
	Net carrying amount	$	283,948
	Equity component	$	61,195
Summary of total interest expense recognized related to the Notes	'
	(In thousands)	June 30, 2014
	Contractual interest expense	$	116
	Amortization of debt issuance costs	14
	Amortization of debt discount	143
	Total interest expense	$	273

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (Ampyra)	6 Months Ended
	Jun. 30, 2014
Minimum	'
Revenue Recognition	'
Contractually obligated inventory holdings period	'10 days
Maximum	'
Revenue Recognition	'
Contractually obligated inventory holdings period	'30 days

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details 2)	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
	customer	customer
Concentration of Credit Risk	'	'
Number of specialty distributors for Qutenza	2	'
Segment and Geographic Information	'	'
Number of reportable operating segments	1	'
Product revenue	'	'
Concentration of Credit Risk	'	'
Number of customers	4	4
Accounts receivable	'	'
Concentration of Credit Risk	'	'
Number of customers	4	3

Sharebased_Compensation_Detail

Share-based Compensation (Details) (USD $)	3 Months Ended		6 Months Ended
In Millions, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share-based compensation expense	'	'	'	'
Share-based compensation expense recognized	$7.60	$6.50	$13.40	$11.50
Weighted average fair value of options granted to employees (in dollars per share)	$15.37	$16.81	$18.18	$15.56
Research and development	'	'	'	'
Share-based compensation expense	'	'	'	'
Share-based compensation expense recognized	1.6	1.5	2.7	2.7
Selling, general, and administrative	'	'	'	'
Share-based compensation expense	'	'	'	'
Share-based compensation expense recognized	$6	$5	$10.70	$8.80

Sharebased_Compensation_Detail1

Share-based Compensation (Details 2) (USD $)	6 Months Ended
Share data in Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014
Share based compensation, other disclosures	'
Total unrecognized compensation costs related to unvested stock options and restricted stock awards that the company expects to recognize	$67,900,000
Weighted average period	'2 years 9 months 18 days
Stock Options	'
Stock Option Activity	'
Balance at the beginning of the period (in shares)	6,486
Granted (in shares)	1,625
Cancelled (in shares)	-129
Exercised (in shares)	-173
Balance at the end of the period (in shares)	7,809
Vested and expected to vest at end of period (in shares)	7,709
Vested and exercisable at end of period (in shares)	4,378
Weighted Average Exercise Price	'
Balance at the beginning of the period (in dollars per share)	$25.61
Granted (in dollars per share)	$37.31
Cancelled (in dollars per share)	$31.31
Exercised (in dollars per share)	$25.35
Balance at the end of the period (in dollars per share)	$27.96
Vested and expected to vest at the end of the period (in dollars per share)	$27.87
Vested and exercisable at the end of the period (in dollars per share)	$24.16
Weighted Average Remaining Contractual Term	'
Balance at the end of the period	'7 years
Vested and expected to vest at the end of the period	'6 years 10 months 24 days
Vested and exercisable at the end of the period	'5 years 4 months 24 days
Intrinsic Value	'
Balance at the end of the period	52,648,000
Vested and expected to vest at the end of the period	52,477,000
Vested and exercisable at the end of the period	$42,555,000
Restricted Stock	'
Restricted Stock Activity	'
Nonvested at the beginning of the period (in shares)	421
Granted (in shares)	284
Vested (in shares)	-4
Forfeited (in shares)	-20
Nonvested at the end of the period (in shares)	681

Earnings_Per_Share_Details

Earnings Per Share (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 17, 2014
					Notes	Notes
Basic and diluted	'	'	'	'	'	'
Net income (in dollars)	$4,685	$3,910	$5,390	$2,772	'	'
Weighted average common shares outstanding used in computing net income per share-basic	41,032	39,960	40,985	39,896	'	'
Plus: net effect of dilutive stock options and unvested restricted common shares	1,400	1,623	1,351	1,415	'	'
Weighted average common shares outstanding used in computing net income per share-diluted	42,432	41,583	42,336	41,311	'	'
Net income per share-basic (in dollars per share)	$0.11	$0.10	$0.13	$0.07	'	'
Net income per share-diluted (in dollars per share)	$0.11	$0.09	$0.13	$0.07	'	'
Earnings per share	'	'	'	'	'	'
Principal	'	'	'	'	$345,000	$345,000
Interest rate (as a percent)	'	'	'	'	1.75%	'

Earnings_Per_Share_Details_2

Earnings Per Share (Details 2)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Stock options and restricted common shares	'	'	'	'
Antidilutive Securities	'	'	'	'
Anti-dilutive securities excluded from computation of earnings per share (in shares)	3,739	1,762	3,859	3,139
Convertible note - Saints Capital	'	'	'	'
Antidilutive Securities	'	'	'	'
Anti-dilutive securities excluded from computation of earnings per share (in shares)	29	39	29	39

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Taxes	'	'	'	'
Income tax (provision) benefit	($6,033)	($4,247)	($8,825)	($2,472)
Effective income tax rate (as a percent)	56.00%	52.00%	62.00%	47.00%

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets Carried at Fair Value:	'	'
Short-term investments	$331,254	$225,891
Long-term investments	121,855	93,299
Recurring basis | Level 1	'	'
Assets Carried at Fair Value:	'	'
Cash equivalents	253,604	28,308
Recurring basis | Level 2	'	'
Assets Carried at Fair Value:	'	'
Short-term investments	331,254	225,891
Long-term investments	121,855	93,299
Recurring basis | Level 3	'	'
Liabilities Carried at Fair Value:	'	'
Put/call liability	167	147
Contingent purchase price	$254	$236

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 2) (USD $)	3 Months Ended	6 Months Ended			3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014	Jun. 30, 2014	Jun. 30, 2014
	Put/call liability	Put/call liability	Put/call liability	Put/call liability	Contingent purchase price	Contingent purchase price
Assets and liabilities measured at fair value on a recurring basis utilizing Level 3 inputs	'	'	'	'	'	'
Balance, beginning of period	$247,000	$147,000	$329,000	$167,000	$245,000	$236,000
Total losses (gains) included in selling, general and administrative expenses	-247,000	20,000	-329,000	'	9,000	18,000
Balance, end of period	'	167,000	'	167,000	254,000	254,000
Milestone payment, minimum (as a percent)	'	'	'	'	0.00%	0.00%
Milestone payment, maximum (as a percent)	'	'	'	'	10.00%	10.00%
Milestone payment, minimum	'	'	'	'	0	0
Milestone payment, maximum	'	'	'	'	$5,000,000	$5,000,000

Investments_Details

Investments (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Investments	'	'
Other-than-temporary declines in the fair values of investments	0	'
Short-term investments classified as cash and cash equivalents	253,600,000	28,300,000
Minimum	'	'
Investments	'	'
Short-term investments maturity term	'3 months	'3 months
Long-term investments maturity term	'1 year	'1 year
Maximum	'	'
Investments	'	'
Short-term investments maturity term	'1 year	'1 year
Long-term investments maturity term	'16 months	'16 months
US Treasury bonds	'	'
Investments	'	'
Amortized Cost	452,947,000	319,123,000
Gross unrealized gains	166,000	69,000
Gross unrealized losses	-4,000	-2,000
Estimated fair value	453,109,000	319,190,000

Investments_Details_2

Investments (Details 2) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Changes in accumulated other comprehensive income	'	'	'	'
Balance at the beginning of the period	'	'	$37	'
Net current period other comprehensive income	14	-29	59	-8
Balance at the end of the period	96	'	96	'
Net Unrealized Gains on Marketable Securities	'	'	'	'
Changes in accumulated other comprehensive income	'	'	'	'
Balance at the beginning of the period	'	'	37	'
Other comprehensive income before reclassifications	'	'	59	'
Net current period other comprehensive income	'	'	59	'
Balance at the end of the period	$96	'	$96	'

Convertible_Senior_Notes_Detai

Convertible Senior Notes (Details) (USD $)	3 Months Ended		6 Months Ended		0 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 17, 2014	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014
					Notes	Notes	Notes	Notes	Notes	Notes
						item	Conversion Terms upon Occurrence of Certain Fundamental Company Changes	Conversion Terms, Event of Default	Convertible Debt Holder	Convertible Debt Holder
									item	Minimum
										item
Convertible senior notes	'	'	'	'	'	'	'	'	'	'
Interest rate (as a percent)	'	'	'	'	'	1.75%	'	'	'	'
Principal amount of Notes purchased by Underwriter	'	'	'	'	'	$45,000,000	'	'	'	'
Net proceeds from offering, after deducting Underwriter's discount and estimated offering expenses payable	'	'	'	'	'	337,600,000	'	'	'	'
Initial conversion rate of common stock	'	'	'	'	'	'	'	'	0.0234968	'
Initial conversion price of convertible notes into common stock (in dollars per share)	'	'	'	'	'	'	'	'	$42.56	'
Number of trading days in the measurement period that the entity's common stock closing price to conversion price must exceed a specified percentage of conversion price to trigger conversion feature of notes	'	'	'	'	'	20	'	'	5	20
Number of trading days triggering conversion of redemption feature	'	'	'	'	'	'30 days	'	'	'5 days	'30 days
Ratio of closing share price to conversion price as a condition for conversion of Convertible Notes (as a percent)	'	'	'	'	'	'	'	'	98.00%	'
Target ratio of closing share price to conversion price as a condition for conversion or redemption of Convertible Notes (as a percent)	'	'	'	'	'	'	'	'	130.00%	130.00%
Number of trading days within which redemption condition is to be met prior to provision of notice	'	'	'	'	'	'5 days	'	'	'	'
Redemption price of debt (as a percent)	'	'	'	'	'	100.00%	'	'	'	'
Principal amount of Notes or an integral multiple thereof in which holder may repurchase the Notes	'	'	'	'	'	'	1,000	'	'	'
Redemption price as percentage of principal amount of notes plus accrued and unpaid interest	'	'	'	'	'	'	100.00%	'	'	'
Minimum percentage of aggregate principal amount held by bondholders to declare notes due and payable	'	'	'	'	'	'	'	25.00%	'	'
In event of default arising out of certain bankruptcy events, percentage of principal amount due and payable	'	'	'	'	'	'	'	100.00%	'	'
Period to comply with covenants	'	'	'	'	'	'270 days	'	'	'	'
Principal	'	'	'	'	345,000,000	345,000,000	'	'	'	'
Less: debt discount, net	'	'	'	'	'	-61,052,000	'	'	'	'
Net carrying amount	'	'	'	'	'	283,948,000	'	'	'	'
Equity component	'	'	'	'	'	61,195,000	'	'	'	'
Debt issuance costs	'	'	'	'	'	7,400,000	'	'	'	'
Debt issuance costs allocated to equity component	'	'	'	'	'	1,200,000	'	'	'	'
Debt issuance costs allocated to liability component	'	'	'	'	'	6,200,000	'	'	'	'
Term of debt	'	'	'	'	'7 years	'	'	'	'	'
Remaining contractual life	'	'	'	'	'	'7 years	'	'	'	'
Effective interest rate on liability component (as a percent)	'	'	'	'	'	4.80%	'	'	'	'
Contractual interest expense	'	'	'	'	'	116,000	'	'	'	'
Amortization of debt issuance costs	'	'	12,000	28,000	'	14,000	'	'	'	'
Amortization of debt discount	'	'	1,487,000	1,169,000	'	143,000	'	'	'	'
Total interest expense	$426,000	$749,000	$518,000	$1,340,000	'	$273,000	'	'	'	'

Collaborations_Alliances_and_O1

Collaborations, Alliances, and Other Agreements (Details) (USD $)

3 Months Ended

6 Months Ended

1 Months Ended

1 Months Ended

6 Months Ended

12 Months Ended

0 Months Ended

1 Months Ended

3 Months Ended

6 Months Ended

0 Months Ended

3 Months Ended

3 Months Ended

6 Months Ended

3 Months Ended

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Dec. 31, 2012

Dec. 31, 2013

Feb. 29, 2012

Jun. 30, 2014

Dec. 31, 2012

Jun. 30, 2014

Jun. 30, 2014

Jun. 30, 2009

Jul. 01, 2009

Aug. 31, 2011

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2009

Jun. 30, 2009

Jul. 07, 2009

Sep. 30, 2011

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2009

Jun. 30, 2014

Jun. 30, 2013

Jun. 30, 2014

Jun. 30, 2013

Sep. 30, 2013

Jun. 30, 2014

Jun. 30, 2014

Dec. 31, 2013

Neuronex Acquisition

Neuronex Acquisition

DZNS

DZNS

DZNS

DZNS

DZNS

Biogen Idec

Biogen Idec

Biogen Idec

Biogen Idec

Biogen Idec

Biogen Idec

Biogen Idec

Biogen Idec

Biogen Idec

Alkermes License Agreement

Alkermes License Agreement

Alkermes License Agreement

Alkermes License Agreement

Alkermes License Agreement

Actavis/Watson

Actavis/Watson

Actavis/Watson

Actavis/Watson

SK

SK

SK

Neuronex

Neuronex Acquisition

Neuronex Acquisition

Neuronex Acquisition

Neuronex Acquisition

Neuronex Acquisition

Maximum

Maximum

Zanaflex Capsules

Zanaflex Capsules

Zanaflex Capsules

Zanaflex Capsules

DZNS

DZNS

DZNS

Achievement of Manufacturing and Regulatory Milestones

Achievement of Sales Milestones

Forecast Revenue

Neuronex Acquisition

Neuronex Acquisition

Neuronex Acquisition

Achievement of Manufacturing and Regulatory Milestones

Achievement of Manufacturing and Regulatory Milestones

Achievement of Sales Milestones

Collaboration agreement

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional payments based on the successful achievement of future regulatory or sales milestones

$5,146,000

$4,664,000

$8,937,000

$10,180,000

'

'

'

'

'

'

'

'

'

$25,000,000

'

'

'

'

$10,000,000

$365,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Amortized license revenue

'

'

'

'

'

'

'

'

'

'

'

110,000,000

'

'

2,300,000

2,300,000

4,500,000

4,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Deferred Revenue

'

'

'

'

'

'

'

'

'

'

'

110,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash received

'

'

'

'

'

'

'

'

'

'

'

'

110,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cost of license payable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

159,000

317,000

7,700,000

'

'

'

'

'

'

'

'

Payment for product license

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7,700,000

'

'

'

'

'

'

'

'

'

'

'

'

Amount of significant and incremental discount related to the supply agreement

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Identified non-contingent deliverables value on standalone basis, if sold separately

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Current estimate of license revenue recognition period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'12 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Portion of milestone payment from Acorda to Alkermes (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7.00%

'

'

'

'

'

'

'

'

'

'

'

Royalty revenues

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,400,000

2,500,000

3,800,000

5,100,000

'

'

'

'

Revenue recognized

89,719,000

80,125,000

164,182,000

144,209,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,300,000

1,100,000

2,200,000

1,600,000

'

'

'

'

Cost of sales

18,899,000

16,935,000

34,428,000

30,418,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,300,000

1,100,000

2,200,000

1,600,000

'

'

'

'

Business Acquisition

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments recorded as research and development expense

'

'

'

'

'

'

2,000,000

'

1,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Payments to complete the acquisition

'

'

'

'

6,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Royalty payment period

'

'

'

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum contingent acquisition payment

'

'

'

'

'

'

'

'

'

18,000,000

105,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

8,000,000

3,000,000

'

Cost of license

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

'

Tangible net assets acquired, primarily the taxable amount of net operating loss carryforwards

'

'

'

'

3,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Holdback provision

'

'

'

'

'

300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

120,000

Upfront payments recorded as research and development expense

'

'

'

'

2,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Advance funding payments recorded as research and development expense

'

'

'

'

$1,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	31-May-14	Jun. 30, 2014	Jun. 17, 2014
In Thousands, unless otherwise specified	sqft	Notes	Notes
Commitments and Contingencies	'	'	'
Additional lease option rights exercised (in square feet)	25,405	'	'
Commitments and contingencies	'	'	'
Aggregate loan	'	$345,000	$345,000
Interest rate (as a percent)	'	1.75%	'