CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 161,778	$ 159,973
Short-term investments	469,515	496,788
Contracts receivable	9,823	11,102
Inventories	7,537	8,033
Investment in Regulus Therapeutics Inc.	63,586	52,096
Other current assets	9,814	7,518
Total current assets	722,053	735,510
Property, plant and equipment, net	86,641	86,198
Licenses, net	4,101	4,572
Patents, net	16,383	15,517
Deposits and other assets	5,438	5,359
Total assets	834,616	847,156
Current liabilities:
Accounts payable	9,869	11,009
Accrued compensation	4,328	12,168
Accrued liabilities	27,903	22,092
Current portion of long-term obligations	4,308	4,408
Current portion of deferred contract revenue	54,428	48,135
Total current liabilities	100,836	97,812
Long-term deferred contract revenue	130,755	142,790
2 3/4 percent convertible senior notes	152,005	150,334
Long-term obligations, less current portion	5,523	6,542
Long-term financing liability for leased facility	71,395	71,288
Total liabilities	460,514	468,766
Stockholders' equity:
Common stock, $0.001 par value; 200,000,000 shares authorized, 117,541,860 and 116,471,371 shares issued and outstanding at March 31, 2014 and December 31, 2013, respectively	118	116
Additional paid-in capital	1,343,874	1,324,804
Accumulated other comprehensive income	29,000	21,080
Accumulated deficit	(998,890)	(967,610)
Total stockholders' equity	374,102	378,390
Total liabilities and stockholders' equity	$ 834,616	$ 847,156