CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 92,326	$ 122,927
Accounts receivable	3,000	2,629
Contract asset		557
Prepaid expenses and other current assets	5,765	5,565
Total current assets	101,091	131,678
Property and equipment, net	5,561	2,499
Other assets	2,725	2,663
Total assets	109,377	136,840
Current liabilities:
Accounts payable	3,299	3,126
Refund liability		21,233
Accrued expenses	19,811	16,207
Total current liabilities	23,110	40,566
Notes payable, net of deferred financing costs	70,350	40,809
Contract liability	9,443
Other long-term liabilities	1,671	1,979
Total liabilities	104,574	83,354
Stockholders' equity:
Series A convertible preferred stock, $0.001 par value; 25,000,000 shares authorized, 4,300 shares issued and outstanding at June 30, 2022 and 4,575 shares issued and outstanding at December 31, 2021	4,043	4,302
Common stock, $0.001 par value; 150,000,000 shares authorized, 37,206,457 issued and 37,199,150 outstanding at June 30, 2022 and 36,797,561 issued and 36,790,254 outstanding at December 31, 2021	37	37
Additional paid-in capital	470,222	459,852
Treasury stock at cost, 7,307 shares at June 30, 2022 and December 31, 2021
Accumulated deficit	(469,499)	(410,705)
Total stockholders' equity	4,803	53,486
Total liabilities and stockholders' equity	$ 109,377	$ 136,840