Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 44,347	$ 30,360
Short-term investments	2,504	48,994
Accounts receivable	1,818	3,313
Prepaid and other current assets	2,807	6,843
Total current assets	51,476	89,510
Long-term investments		2,543
Other assets, noncurrent	472	528
Right-of-use assets	2,744	1,832
Property and equipment, net	970	433
Total assets	55,662	94,846
Current liabilities:
Accounts payable	6,419	5,931
Accrued compensation	1,467	2,476
Deferred revenue	230	1,983
Other accrued liabilities	4,072	6,743
Operating lease liability	1,977	663
Total current liabilities	14,165	17,796
Operating lease liability, noncurrent	408	981
Total liabilities	14,573	18,777
Commitments and Contingencies (Note 7)
Stockholders’ equity:
Preferred stock, $0.001 par value, 5,000,000 shares authorized; zero shares issued and outstanding
Common stock, $0.001 par value, 100,000,000 shares authorized; 31,409,707 and 22,097,820 shares issued and outstanding at December 31, 2021 and 2020, respectively	31	22
Additional paid-in capital	443,752	390,803
Accumulated other comprehensive income		5
Accumulated deficit	(402,694)	(314,761)
Total stockholders’ equity	41,089	76,069
Total liabilities and stockholders’ equity	$ 55,662	$ 94,846