CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 30,678	$ 63,474
Short-term investments	176,571	148,703
Accounts receivable, net	5,778	5,932
Inventories	13,580	15,206
Receivable from collaboration	15,133	428
Prepaid and other current assets	4,202	6,288
Total current assets	245,942	240,031
Property, plant and equipment, net	7,831	9,206
Long-term investments		17,527
Restricted cash	460	460
Total assets	254,233	267,224
Current liabilities:
Accounts payable	3,757	3,732
Accrued expenses	23,351	28,916
Deferred revenues	6,346	6,346
Total current liabilities	33,454	38,994
Long-term liabilities:
Deferred revenues	42,148	45,196
Other long-term liabilities	2,239	2,438
Total liabilities	77,841	86,628
Commitments and contingencies (Notes I & J)
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; 21,390,188 and 21,306,413 shares issued and outstanding at June 30, 2012 and December 31, 2011, respectively	214	213
Additional paid-in capital	628,508	625,133
Accumulated other comprehensive loss	(3,325)	(4,842)
Accumulated deficit	(449,005)	(439,908)
Total stockholders' equity	176,392	180,596
Total liabilities and stockholders' equity	$ 254,233	$ 267,224