CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 93,337	$ 128,797
Short-term investments	610,467	650,386
Contracts receivable	16,480	11,356
Inventories	6,520	6,899
Investment in Regulus Therapeutics Inc.	19,703	24,792
Other current assets	17,403	14,773
Total current assets	763,910	837,003
Property, plant and equipment, net	90,365	90,233
Patents, net	20,144	19,316
Deposits and other assets	1,400	1,348
Total assets	875,819	947,900
Current liabilities:
Accounts payable	19,464	28,355
Accrued compensation	6,338	16,065
Accrued liabilities	26,172	28,105
Current portion of long-term obligations	8,826	9,029
Current portion of deferred contract revenue	63,695	67,322
Total current liabilities	124,495	148,876
Long-term deferred contract revenue	123,084	134,306
Long-term obligations, less current portion	2,372	2,341
Long-term financing liability for leased facility	72,251	72,217
Total liabilities	717,657	747,110
Stockholders' equity:
Common stock, $0.001 par value; 300,000,000 shares authorized, 120,717,810 and 120,351,480 shares issued and outstanding at March 31, 2016 and December 31, 2015, respectively	121	120
Additional paid-in capital	1,331,945	1,309,107
Accumulated other comprehensive loss	(16,115)	(13,565)
Accumulated deficit	(1,157,789)	(1,094,872)
Total stockholders' equity	158,162	200,790
Total liabilities and stockholders' equity	875,819	947,900
1 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes	345,265	339,847
2 3/4 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes	$ 50,190	$ 49,523