CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 565,119	$ 397,664
Short-term investments	1,494,151	1,494,711
Contracts receivable	24,004	76,204
Inventories	24,099	21,965
Other current assets	131,045	140,163
Total current assets	2,238,418	2,130,707
Property, plant and equipment, net	179,316	181,077
Patents, net	29,373	27,937
Deposits and other assets	49,962	50,034
Total assets	2,497,069	2,389,755
Current liabilities:
Accounts payable	14,658	17,199
Accrued compensation	30,222	65,728
Accrued liabilities	75,150	90,161
Income taxes payable	1,875	1,324
1 percent convertible senior notes, net	61,876	308,809
Current portion of long-term obligations	7,972	7,301
Current portion of deferred contract revenue	102,072	108,376
Total current liabilities	293,825	598,898
Long-term deferred contract revenue	379,874	424,046
Long-term obligations, less current portion	22,055	23,409
Long-term mortgage debt	60,019	59,984
Total liabilities	1,914,395	1,646,473
Stockholders' equity:
Common stock, $0.001 par value; 300,000,000 shares authorized, 141,021,583 and 140,365,594 shares issued and outstanding at June 30, 2021 (unaudited) and December 31, 2020, respectively	141	140
Additional paid-in capital	1,910,379	1,895,519
Accumulated other comprehensive loss	(25,796)	(21,071)
Accumulated deficit	(1,302,050)	(1,131,306)
Total stockholders' equity	582,674	743,282
Total liabilities and stockholders' equity	2,497,069	2,389,755
0 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes, net	617,399	0
0.125 Percent Convertible Senior Notes [Member]
Current liabilities:
Convertible senior notes, net	$ 541,223	$ 540,136