BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 182,348	$ 190,518
Investments, short-term	43,796	43,844
Accounts receivable, net of allowance for credit losses of $35 and $42, respectively	21,646	25,063
Inventories	11,385	8,479
Prepaid expenses and other current assets	1,609	1,965
Total current assets	260,784	269,869
Property and equipment, net	6,791	5,311
Operating lease right-of-use asset	5,634	5,805
Other non-current assets	204	204
Total assets	273,413	281,189
Current liabilities:
Accounts payable	9,057	7,209
Accrued expenses	10,365	13,516
Total current liabilities	19,422	20,725
Notes payable	24,804	24,746
Operating lease liability, non-current portion	5,959	5,886
Other non-current liability	97	85
Total liabilities	50,282	51,442
Stockholders' equity:
Preferred Stock, $0.001 par value, 10,000,000 shares authorized; no shares issued and outstanding at March 31, 2021 and December 31, 2020	0	0
Common Stock, $0.001 par value per share; 200,000,000 shares authorized; 27,203,073 and 27,069,276 issued and outstanding at March 31, 2021 and December 31, 2020, respectively	27	27
Additional paid-in capital	476,658	467,038
Accumulated other comprehensive income	9	29
Accumulated deficit	(253,563)	(237,347)
Total stockholders' equity	223,131	229,747
Total liabilities and stockholders' equity	$ 273,413	$ 281,189