CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	[1]
Current assets:
Cash and cash equivalents	$ 49,727	$ 14,280
Restricted cash	431	540
Accounts receivable, net	4,613	5,063
Prepaid expenses and other current assets	2,827	3,039
Total current assets	57,598	22,922
Property and equipment, net	4,012	5,477
Right-of-use assets, operating leases	2,740	7,737
Other non-current assets	684	873
Total assets	65,034	37,009
Current liabilities:
Accounts payable	791	928
Accrued expenses and other current liabilities	5,823	6,552
Note payable, current	2,226	1,854
Operating lease liabilities	3,222	6,800
Total current liabilities	12,062	16,134
Note payable, net of current	1,094	1,466
Operating lease liabilities, non-current	0	1,814
Other long-term liabilities	1,154	1,780
Total liabilities	14,310	21,194
Commitments and contingencies (Note 13)
Stockholders’ equity:
Common stock, $0.001 par value - 142,857 shares authorized, 15,491 and 9,743 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	15	10
Additional paid-in capital	350,822	308,065
Accumulated deficit	(299,006)	(291,163)
Accumulated other comprehensive loss	(1,107)	(1,097)
Total stockholders’ equity	50,724	15,815
Total liabilities and stockholders’ equity	$ 65,034	$ 37,009

[1] Derived from the Company’s audited consolidated financial statements as of December 31, 2020.