CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
CURRENT ASSETS
Cash and cash equivalents	$ 63,419	$ 53,581
Short-term investments	83,560	142,851
Accounts receivable, net of allowance for credit losses of $264 and $263, respectively	14,246	13,611
Inventory	11,498	5,633
Prepaid expenses and other current assets	3,143	2,565
Total current assets	175,866	218,241
Property and equipment, net	8,992	4,527
Operating lease right-of-use assets	5,248	0
Other non-current assets	400	374
TOTAL ASSETS	190,506	223,142
CURRENT LIABILITIES
Accounts payable	3,198	3,271
Accrued liabilities and other	12,353	10,199
Operating lease liabilities, current portion	1,339	0
Total current liabilities	16,890	13,470
Long-term borrowings	34,973	39,455
Operating lease liabilities, net of current portion	4,166	0
Other long-term liabilities	57	854
TOTAL LIABILITIES	56,086	53,779
Commitments and contingencies (Note 6)
STOCKHOLDERS’ EQUITY
Preferred stock, $0.0001 par value; 5,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.0001 par value; 100,000,000 shares authorized; 33,674,085 and 32,583,220 shares issued and outstanding, respectively	3	3
Additional paid-in capital	429,914	408,113
Accumulated other comprehensive income	352	524
Accumulated deficit	(295,849)	(239,277)
TOTAL STOCKHOLDERS’ EQUITY	134,420	169,363
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 190,506	$ 223,142