CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 102,624	$ 59,522
Accounts and other receivables	2,034	2,218
Prepaid expenses and other current assets	11,213	12,610
Total current assets	115,871	74,350
Property and equipment, net	254	209
Deposits Assets, Noncurrent	12,296	12,571
Other assets	7,987	9,000
Total assets	136,408	96,130
Current liabilities:
Accounts payable	469	149
Accrued compensation	933	1,001
Other current liabilities	2,718	2,457
Deferred revenue	5,098	5,173
Total current liabilities	9,218	8,780
Long-term deferred revenue	20,183	21,334
Other long-term liabilities	1,709	2,035
Total liabilities	31,110	32,149
Contingencies (Note 5)
Stockholders’ equity:
Common stock and additional paid-in capital — $0.001 par value; 100,000,000 shares authorized; 43,020,610 and 39,161,214 shares issued, respectively; 30,877,177 and 27,017,781 shares outstanding, respectively	298,037	258,756
Accumulated other comprehensive income	122	122
Accumulated deficit	(111,128)	(113,164)
Treasury stock at cost: 12,143,433 and 12,143,433 shares, respectively	(81,733)	(81,733)
Total stockholders’ equity	105,298	63,981
Total liabilities and stockholders’ equity	$ 136,408	$ 96,130