Condensed Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 94,575	$ 69,466
Short-term investments	41,497	78,016
Accounts receivable, net	11,106	9,070
Inventories	11,960	9,989
Prepaid expenses and other current assets	4,757	6,787
Total current assets	163,895	173,328
Property and equipment, net	2,777	2,844
Restricted cash	310	310
Other non-current assets	2,680	2,832
Total assets	169,662	179,314
Current liabilities:
Accounts payable	2,923	2,598
Accrued liabilities	13,291	16,957
Total current liabilities	16,214	19,555
Long-term debt	48,574	48,533
Other liabilities	3,720	3,726
Total liabilities	68,508	71,814
Commitments and contingencies (Note 7)
Preferred stock, $0.001 par value
Shares authorized: 5,000,000 at March 31, 2021 and December 31, 2020 Shares issued and outstanding: none at March 31, 2021 and December 31, 2020
Common stock, $0.001 par value
Shares authorized: 100,000,000 at March 31, 2021 and December 31, 2020 Shares issued and outstanding: 34,438,290 and 34,249,649 at March 31, 2021 and December 31, 2020, respectively	34	34
Additional paid-in capital	350,699	346,318
Accumulated other comprehensive income	6	39
Accumulated deficit	(249,585)	(238,891)
Total stockholders’ equity	101,154	107,500
Total liabilities and stockholders’ equity	$ 169,662	$ 179,314