Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 24,132	$ 24,361
Short-term investments	119,715	134,971
Accounts receivable	5,626	4,862
Inventories	8,490	8,032
Prepaid and other current assets	3,184	4,069
Total current assets	161,147	176,295
Property and equipment, net	10,915	11,217
Operating leases right-of-use assets	4,057	4,284
Restricted cash	811	811
Other assets	132	114
Total assets	177,062	192,721
Current liabilities:
Accounts payable	2,587	1,689
Accrued expenses and other current liabilities	6,409	7,859
Lease liabilities	1,663	1,529
Total current liabilities	10,659	11,077
Long-term lease liabilities	3,350	3,642
Term loan, net	39,890	39,760
Total liabilities	53,899	54,479
Commitments and contingencies (Note 10)
Stockholders' equity:
Common stock, $0.001 par value, 900,000,000 shares authorized, 27,485,685 shares issued and outstanding as of March 31, 2022 and 27,366,746 shares issued and outstanding as of December 31, 2021	27	27
Preferred stock, $0.001 par value, 100,000,000 shares authorized, no shares issued and outstanding as of March 31, 2022 and December 31, 2021	0	0
Additional paid-in capital	620,106	617,511
Accumulated other comprehensive loss	(98)	(20)
Accumulated deficit	(496,872)	(479,276)
Total stockholders' deficit	123,163	138,242
Total liabilities and stockholders' equity	$ 177,062	$ 192,721