Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 41,789	$ 59,537
Prepaid expenses and other current assets	1,035	1,915
Total current assets	42,824	61,452
Restricted cash	270	270
Property and equipment, net	538	556
Operating lease right-of-use asset	1,926	2,478
Total assets	45,558	64,756
Current liabilities:
Accounts payable	990	3,650
Accrued and other liabilities	7,904	10,356
Total current liabilities	8,894	14,006
Noncurrent operating lease liability	917	1,666
Warrant liabilities	496
Total liabilities	10,307	15,672
Commitments and contingencies
Convertible preferred stock; $0.0001 par value; 10,000 shares authorized as of June 30, 2022 and December 31, 2021; 0 and 1000 shares issued and outstanding as of June 30, 2022 and December 31, 2021, respectively; $35,000 liquidation preference as of June 30, 2022 and December 31, 2021 (Note 7)		40,702
Stockholders' equity:
Convertible preferred stock; $0.0001 par value; 10,000 shares authorized as of June 30, 2022 and December 31, 2021; 1,000 and 0 shares issued and outstanding as of June 30, 2022 and December 31, 2021, respectively; $35,000 liquidation preference as of June 30, 2022 and December 31, 2021 (Note 7)	22,342
Common stock, $0.0001 par value, 200,000 shares authorized as of June 30, 2022 and December 31, 2021; 4,865 and 3,857 shares issued and outstanding as of June 30, 2022 and December 31, 2021, respectively
Additional paid-in capital	508,787	499,708
Accumulated deficit	(495,878)	(491,326)
Total stockholders' equity	35,251	8,382
Total liabilities, convertible preferred stock and stockholders' equity	$ 45,558	$ 64,756