Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 12,872	$ 21,407
Accounts receivable, net of allowance for doubtful accounts of $22 and $16 as of December 31, 2021 and 2020	147	232
Prepaid expenses and other current assets	462	401
Other receivable due from related party	0	618
Total current assets	13,481	22,658
Property and equipment, net	182	145
Operating lease right-of-use asset, net	1,883	567
Other assets	172	54
Total assets	15,718	23,424
Current liabilities:
Accounts payable	507	746
Accrued expenses and other current liabilities	2,121	2,205
Deferred revenue	847	683
Operating lease liability - current	237	614
Total current liabilities	3,712	4,248
Operating lease liability - noncurrent	1,631	0
Total liabilities	5,343	4,248
Commitments and contingencies (Notes 1,2,5 and 14)
Stockholders’ equity:
Preferred stock, $0.001 par value, 25,000,000 shares authorized as of December 31, 2021 and December 31, 2020; no shares issued and outstanding as of December 31, 2021 and 2020	0	0
Common stock, $0.001 par value, 100,000,000 shares authorized as of December 31, 2021 and 2020; 16,871,265 and 16,297,381 shares issued and outstanding as of December 31, 2021 and 2020, respectively	17	16
Additional paid-in capital	139,055	135,234
Accumulated deficit	(128,697)	(116,074)
Total stockholders’ equity	10,375	19,176
Total liabilities and stockholders’ equity	$ 15,718	$ 23,424