CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 107,650	$ 124,482
Short-term investments	264,261	249,964
Contracts receivable	1,172	522
Inventories	5,809	6,121
Investment in Regulus Therapeutics Inc.	44,863	33,622
Other current assets	8,074	8,727
Total current assets	431,829	423,438
Property, plant and equipment, net	89,694	91,084
Licenses, net	6,010	6,579
Patents, net	19,604	18,646
Deposits and other assets	5,824	5,939
Total assets	552,961	545,686
Current liabilities:
Accounts payable	5,385	10,239
Accrued compensation	3,818	7,878
Accrued liabilities	17,758	15,401
Accrued income taxes	3,582
Current portion of long-term obligations	4,508	4,879
Current portion of deferred contract revenue	35,244	35,925
Total current liabilities	70,295	74,322
Long-term deferred contract revenue	58,816	66,656
2 3/4 percent convertible senior notes	145,533	143,990
Long-term obligations, less current portion	6,498	7,402
Long-term financing liability for leased facility	70,728	70,550
Total liabilities	351,870	362,920
Stockholders' equity:
Common stock, $0.001 par value; 200,000,000 shares authorized, 102,695,200 and 101,481,134 shares issued and outstanding at March 31, 2013 and December 31, 2012, respectively	103	102
Additional paid-in capital	1,091,842	1,077,150
Accumulated other comprehensive gain	17,784	12,480
Accumulated deficit	(908,638)	(906,966)
Total stockholders' equity	201,091	182,766
Total liabilities and stockholders' equity	$ 552,961	$ 545,686