Condensed consolidated balance sheets - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 49,720	$ 178,387
Short-term investments	94,371	15,110
Accounts receivable	4,100	5,005
Inventory	21,293	15,671
Prepaid expenses and other current assets	1,999	3,951
Total current assets	171,483	218,124
Property and equipment, net	12,649	11,304
Right-of-use assets, net	7,530
Long-term investments	22,816	9,966
Other long-term assets	1,381	1,491
Restricted cash	284	284
Total assets	216,143	241,169
Current liabilities:
Accounts payable	2,822	3,944
Accrued expenses and other current liabilities	5,281	10,917
Deferred revenue	3,918	3,305
Lease liabilities, short-term	729
Total current liabilities	12,750	18,166
Deferred rent, long term		813
Lease liabilities, long-term	7,728
Other long-term liabilities	698	1,210
Total liabilities	21,176	20,189
Commitments and contingencies (Note 17)
Stockholders' equity:
Preferred stock, $0.01 par value: 10,000,000 shares authorized at June 30, 2022 and December 31, 2021; zero shares issued and outstanding at June 30, 2022 and December 31, 2021
Additional paid-in capital	538,598	535,693
Accumulated deficit	(343,132)	(315,112)
Accumulated other comprehensive loss	(919)	(16)
Total stockholders' equity	194,967	220,980
Total liabilities and stockholders' equity	216,143	241,169
Common Class A
Stockholders' equity:
Common stock	365	346
Common Class B
Stockholders' equity:
Common stock	$ 55	$ 69