CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
CURRENT ASSETS
Cash and cash equivalents	$ 10,435	$ 25,120
Short-term investments	81,345	97,103
Accounts receivable, net of allowance for doubtful accounts of $238 and $263, respectively	11,720	8,486
Inventory	5,452	3,343
Prepaid expenses and other current assets	2,510	1,990
Total current assets	111,462	136,042
Long-term investments	1,278	0
Property and equipment, net	3,954	2,154
Other non-current assets	315	325
TOTAL ASSETS	117,009	138,521
CURRENT LIABILITIES
Accounts payable	2,811	2,146
Accrued liabilities and other	11,605	6,860
Current portion of long-term borrowings	4,358	0
Total current liabilities	18,774	9,006
Long-term borrowings	34,865	38,963
Other long-term liabilities	362	360
TOTAL LIABILITIES	54,001	48,329
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; 25,163,803 and 24,450,757 shares issued and outstanding, respectively	3	3
Additional paid-in capital	258,121	246,927
Accumulated other comprehensive income	464	439
Accumulated deficit	(195,580)	(157,177)
TOTAL STOCKHOLDERS’ EQUITY	63,008	90,192
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 117,009	$ 138,521