Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 114,346	$ 182,348
Short-term investments	187,921	157,140
Accounts receivable, net	26,899	25,600
Inventories	42,873	39,185
Prepaid expenses and other current assets	5,387	5,529
Total current assets	377,426	409,802
Restricted cash	33,311	33,311
Property and equipment, net	13,882	12,964
Operating lease right-of-use assets	6,962	7,231
Other assets	161	156
Total assets	431,742	463,464
Current liabilities:
Accounts payable	5,149	1,763
Accrued compensation and related benefits	13,478	24,948
Accrued expenses and other current liabilities	18,610	13,789
Accrued warranty liability	3,628	3,704
Deferred revenue, current	6,833	6,340
Operating lease liabilities, current	1,192	1,151
Total current liabilities	48,890	51,695
Accrued interest, noncurrent	840	721
Deferred revenue, noncurrent	194	312
Operating lease liabilities, noncurrent	6,581	6,893
Term loan, noncurrent	29,784	29,762
Total liabilities	86,289	89,383
Commitments and contingencies (Note 6)
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000 shares authorized, and no shares issued and outstanding as of March 31, 2022 and December 31, 2021	0	0
Common stock, $0.001 par value; 300,000 shares authorized as of March 31, 2022 and December 31, 2021; 47,712 and 42,241 shares issued and outstanding as of March 31, 2022 and December 31, 2021, respectively	48	47
Additional paid-in capital	1,008,940	1,000,212
Accumulated other comprehensive (loss) income	(649)	(184)
Accumulated deficit	(662,886)	(625,994)
Total stockholders' equity	345,453	374,081
Total liabilities and stockholders' equity	$ 431,742	$ 463,464