CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 11,496	$ 25,120
Short-term investments	91,780	97,103
Accounts receivable, net of allowance for doubtful accounts of $288 and $263, respectively	9,404	8,486
Inventory	4,436	3,343
Prepaid expenses and other current assets	1,902	1,990
Total current assets	119,018	136,042
Long-term investments	5,262	0
Property and equipment, net	2,532	2,154
Other non-current assets	310	325
TOTAL ASSETS	127,122	138,521
Current liabilities:
Accounts payable	2,450	2,146
Accrued liabilities and other	7,469	6,860
Total current liabilities	9,919	9,006
Long-term borrowings	39,093	38,963
Other long-term liabilities	363	360
TOTAL LIABILITIES	49,375	48,329
Commitments and contingencies
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; 24,761,157 and 24,450,757 shares issued and outstanding, respectively	3	3
Additional paid-in capital	252,404	246,927
Accumulated other comprehensive income	516	439
Accumulated deficit	(175,176)	(157,177)
TOTAL STOCKHOLDERS’ EQUITY	77,747	90,192
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 127,122	$ 138,521