Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net loss	$ (13,504)	$ (18,735)	$ (36,267)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,630	1,083	462
Accretion of premium (discount) on marketable investment securities	2,956	2,005	1,379
Shares issued for payment of services	549	0	0
Non-cash interest expense	10,982	17,239	18,115
Non-cash royalties	(39,804)	(55,993)	(57,467)
Realized gain on sale of marketable investment securities	(4)	(4)	0
Loss on disposal of equipment	41	0	0
Loss on extinguishment of debt	0	0	646
Compensation expense on share-based awards	9,437	7,548	4,100
(Increase) decrease in operating assets:
Accounts receivable	(11,324)	(16,010)	18,663
Inventory	3,663	0	0
Prepaid expenses, other current assets and other assets	(466)	1,803	(2,948)
(Decrease) increase in operating liabilities:
Accounts payable and accrued expenses	11,859	1,321	(3,425)
Other liabilities	(1,331)	(1,249)	84
Net cash used in operating activities	(24,316)	(60,992)	(56,658)
Cash flows from investing activities:
Sales of marketable investment securities	11,850	7,628	240
Maturities of marketable investment securities	96,021	111,879	86,428
Purchases of marketable investment securities	(156,842)	(124,809)	(111,380)
Acquisitions of property and equipment	(1,142)	(1,187)	(3,407)
Net cash used in investing activities	(50,113)	(6,489)	(28,119)
Cash flows from financing activities:
Proceeds from issuance of non-recourse debt	0	0	145,000
Principal payments on debt	0	0	(213,848)
Excess tax benefit from stock options	178	0	0
Payment of debt issuance costs	0	0	(96)
Net proceeds from the sale of common stock and exercise of stock options	107,940	2,561	108,163
Decrease in restricted cash and cash equivalents	0	0	50,784
Net cash provided by financing activities	108,118	2,561	90,003
Effect of exchange rate changes on cash	44	(10)	5
Net increase (decrease) in cash and cash equivalents	33,733	(64,930)	5,231
Cash and cash equivalents at beginning of period	17,471	82,401	77,170
Cash and cash equivalents at end of period	51,204	17,471	82,401
Supplemental Disclosures of Cash Flow Information
Cash paid for interest	952	954	27,109
Cash paid for income taxes	4	0	0
Supplemental Disclosure of Non-cash Investing and Financing Activities
6.1 million shares of NPS common stock issued in connection with the Takeda Termination and Transition agreement, see note 10	55,403	0	0
Unrealized gains (losses) on marketable investment securities	7	111	(102)
Accrued acquisition of equipment	428	96	353
Noncash principal payments	26,915	52,050	19,899
Conversion of 5.75% convertible notes	$ 0	$ 0	$ 33,260