Consolidated Statements of Stockholders' Deficit (USD $) In Thousands, except Share data	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit	Total
Beginning balances at Dec. 31, 2011		$ 86	$ 944,344	$ (96)	$ (990,450)	$ (46,116)
Beginning balances, shares at Dec. 31, 2011		86,081,167
Stock options exercised		1	2,407			2,408
Stock options exercised, shares		481,058
Restricted stock vesting			149			149
Restricted stock vesting, shares		171,271
Compensation expense on share-based awards			7,298			7,298
Net proceeds from sale of shares			254			254
Net proceeds from sale of shares, shares		45,553
Other comprehensive income (loss)				101		101
Net loss					(18,735)	(18,735)
Ending balances at Dec. 31, 2012		87	954,452	5	(1,009,185)	(54,641)
Ending balances, shares at Dec. 31, 2012		86,779,049
Stock options exercised		3	14,528			14,531
Stock options exercised, shares		2,521,764
Restricted stock vesting		0	339			339
Restricted stock vesting, shares		211,389
Compensation expense on share-based awards			8,480			8,480
Excess tax benefit from stock options			178			178
Stock issued in connection with the Takeda Termination and Transition agreement		6	55,397			55,403
Stock issued in connection with the Takeda Termination and Transition agreement, shares		6,128,641
Net proceeds from sale of shares		7	94,046			94,053
Net proceeds from sale of shares, shares		6,972,937
Other comprehensive income (loss)				51		51
Net loss					(13,504)	(13,504)
Ending balances at Dec. 31, 2013		103	1,127,420	56	(1,022,689)	104,890
Ending balances, shares at Dec. 31, 2013		102,613,780
Stock options exercised		1	9,317			9,318
Stock options exercised, shares		1,245,034				(1,245,000)
Restricted stock vesting		0	3,109			3,109
Restricted stock vesting, shares		162,877
Compensation expense on share-based awards			9,740			9,740
Excess tax benefit from stock options			312			312
Net proceeds from sale of shares		0	955			955
Net proceeds from sale of shares, shares		40,120
Conversion of 5.75% convertible notes		3	16,532			16,535
Conversion of 5.75% convertible notes, shares		3,041,451
Other comprehensive income (loss)				(2,329)		(2,329)
Net loss					(8,705)	(8,705)
Ending balances at Dec. 31, 2014		$ 107	$ 1,167,385	$ (2,273)	$ (1,031,394)	$ 133,825
Ending balances, shares at Dec. 31, 2014		107,103,262