CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 542,513	$ 869,191
Short-term investments	1,509,880	1,245,782
Contracts receivable	26,122	61,896
Inventories	24,032	24,806
Other current assets	150,577	143,374
Total current assets	2,253,124	2,345,049
Property, plant and equipment, net	177,724	178,069
Patents, net	29,295	29,005
Deposits and other assets	58,949	59,567
Total assets	2,519,092	2,611,690
Current liabilities:
Accounts payable	16,125	11,904
Accrued compensation	16,525	38,810
Accrued liabilities	99,256	88,560
Income taxes payable	901	36
Current portion of long-term obligations	4,206	3,526
Current portion of deferred contract revenue	91,437	97,714
Total current liabilities	228,450	240,550
Long-term deferred contract revenue	333,138	351,879
Long-term obligations, less current portion	25,710	26,378
Long-term mortgage debt	59,462	59,713
Total liabilities	1,809,518	1,839,953
Stockholders' equity:
Common stock, $0.001 par value; 300,000,000 shares authorized, 141,753,122 and 141,210,015 shares issued and outstanding at March 31, 2022 (unaudited) and December 31, 2021, respectively	142	141
Additional paid-in capital	1,983,078	1,964,167
Accumulated other comprehensive loss	(48,578)	(32,668)
Accumulated deficit	(1,225,068)	(1,159,903)
Total stockholders' equity	709,574	771,737
Total liabilities and stockholders' equity	2,519,092	2,611,690
0 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes, net	619,898	619,119
0.125 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes, net	$ 542,860	$ 542,314