Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 48,523	$ 57,626
Marketable securities	29,683	54,415
Prepaid expenses and other current assets	2,914	3,561
Assets held for sale	541	0
Restricted Cash, Current	1,780	0
Total current assets	83,441	115,602
Restricted cash	0	1,780
Operating lease, right-of-use asset	0	23,168
Property and equipment, net	0	6,095
Total assets	83,441	146,645
Current liabilities:
Accounts payable	1,080	2,454
Accrued expenses and other current liabilities	4,902	8,271
Operating lease liability, current portion	0	3,824
Total current liabilities	5,982	14,549
Operating lease liability, net of current portion	0	26,138
Total liabilities	5,982	40,687
Commitments and contingencies (Note 10)
Stockholders' Equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized; no shares issued or outstanding	0	0
Common stock, $0.001 par value; 150,000,000 shares authorized; 60,648,821 and 60,639,909 shares issued and outstanding as of March 31, 2023 and December 31, 2022, respectively	61	61
Additional paid-in capital	508,613	508,107
Accumulated other comprehensive loss	(16)	(181)
Accumulated deficit	(431,199)	(402,029)
Total stockholders' equity	77,459	105,958
Total liabilities and stockholders' equity	$ 83,441	$ 146,645