CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 414,155	$ 397,664
Short-term investments	1,405,840	1,494,711
Contracts receivable	23,397	76,204
Inventories	22,199	21,965
Other current assets	123,827	140,163
Total current assets	1,989,418	2,130,707
Property, plant and equipment, net	180,413	181,077
Patents, net	28,795	27,937
Deposits and other assets	49,925	50,034
Total assets	2,248,551	2,389,755
Current liabilities:
Accounts payable	9,506	17,199
Accrued compensation	29,263	65,728
Accrued liabilities	78,766	90,161
Income taxes payable	1,326	1,324
Current portion of 1 percent convertible senior notes, net	61,816	308,809
Current portion of long-term obligations	7,688	7,301
Current portion of deferred contract revenue	106,740	108,376
Total current liabilities	295,105	598,898
Long-term deferred contract revenue	401,966	424,046
Long-term obligations, less current portion	22,943	23,409
Long-term mortgage debt	60,002	59,984
Total liabilities	1,567,987	1,646,473
Stockholders' equity:
Common stock, $0.001 par value; 300,000,000 shares authorized, 140,924,356 and 140,365,594 shares issued and outstanding at March 31, 2021 (unaudited) and December 31, 2020, respectively	141	140
Additional paid-in capital	1,925,801	1,895,519
Accumulated other comprehensive loss	(24,203)	(21,071)
Accumulated deficit	(1,221,175)	(1,131,306)
Total stockholders' equity	680,564	743,282
Total liabilities and stockholders' equity	2,248,551	2,389,755
0.125 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes, net	540,679	540,136
1 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes, net	$ 247,292	$ 0