CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 33,845	$ 46,293
Investments	183,224	180,750
Accounts receivable, net	8,519	6,410
Inventories	11,292	12,451
Receivable from collaboration	108	263
Assets held for sale	1,931	2,000
Prepaid and other current assets	6,219	6,213
Total current assets	245,138	254,380
Property and equipment, net	2,670	3,297
Restricted cash	460	460
Total assets	248,268	258,137
Current liabilities:
Accounts payable	2,325	3,515
Accrued expenses	15,130	20,338
Deferred revenues	9,262	9,104
Total current liabilities	26,717	32,957
Long-term liabilities:
Deferred revenues	48,376	50,350
Other long-term liabilities	1,922	2,033
Total liabilities	77,015	85,340
Commitments and contingencies (Notes K & L)
Stockholders' equity:
Preferred stock, par value $0.01 per share, 2,000,000 shares authorized; none issued
Common stock, par value $0.01 per share, 58,750,000 shares authorized; 21,554,391 and 21,506,754 shares issued and outstanding at March 31, 2013 and December 31, 2012, respectively	215	215
Additional paid-in capital	634,931	632,487
Accumulated other comprehensive loss	(3,340)	(3,247)
Accumulated deficit	(460,553)	(456,658)
Total stockholders' equity	171,253	172,797
Total liabilities and stockholders' equity	$ 248,268	$ 258,137