CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 57,390	$ 51,490
Marketable Securities, Current	79,476	86,431
Accounts and other receivables	1,923	1,970
Prepaid expenses and other current assets	9,550	13,432
Total current assets	148,339	153,323
Property and equipment, net	376	444
Long-term deposits	4,451	9,658
Debt Securities, Available-for-sale, Noncurrent	17,147	7,286
Other assets	3,705	4,809
Total assets	174,018	175,520
Current liabilities:
Accounts payable	77	2
Accrued compensation	1,125	555
Contract with Customer, Liability, Current	4,649	4,826
Other current liabilities	13,602	11,247
Total current liabilities	19,453	16,630
Long-term deferred revenue	14,334	16,699
Other long-term liabilities	494	896
Total liabilities	34,281	34,225
Commitments and contingencies (Note 5)
Stockholders’ equity:
Common stock and additional paid-in capital	325,351	323,296
Accumulated other comprehensive income (loss)	(401)	412
Accumulated deficit	(97,423)	(100,680)
Treasury stock	(87,790)	(81,733)
Total stockholders’ equity	139,737	141,295
Total liabilities and stockholders’ equity	$ 174,018	$ 175,520