Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Cash flows from operating activities:
Net loss	$ (7,796)	$ (10,563)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	342	247
Accretion of premium on marketable investment securities	502	539
Shares issued for payment of services	549	0
Non-cash interest expense	3,159	5,296
Non-cash royalties	(9,810)	(22,341)
Compensation expense on share based awards	2,956	1,880
(Increase) decrease in operating assets:
Accounts receivable	2,310	84
Inventory	(85)	0
Prepaid expenses, other current assets and other assets	2,261	871
(Decrease) increase in operating liabilities:
Accounts payable and accrued expenses	(3,628)	152
Other liabilities	(79)	(29)
Net cash used in operating activities	(9,319)	(23,864)
Cash flows from investing activities:
Sales of marketable investment securities	2,085	0
Maturities of marketable investment securities	25,922	27,196
Purchases of marketable investment securities	(16,339)	(36,545)
Acquisitions of property and equipment	(288)	(532)
Net cash provided by (used in) investing activities	11,380	(9,881)
Cash flows from financing activities:
Net proceeds from the sale of common stock and exercise of stock options	396	324
Shares withheld for the payment of taxes	(574)	0
Net cash (used in) provided by financing activities	(178)	324
Effect of exchange rate changes on cash	2	(7)
Net increase (decrease) in cash and cash equivalents	1,885	(33,428)
Cash and cash equivalents at beginning of period	17,471	82,401
Cash and cash equivalents at end of period	19,356	48,973
Supplemental Disclosures of Cash Flow Information
Cash paid for interest	235	237
Cash paid for income taxes	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
Unrealized gains on marketable investment securities	9	100
Accrued acquisition of property and equipment	3	228
Noncash reduction of debt	$ 6,278	$ 19,584