CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 12,874	$ 8,040
Short-term investments	48,867	48,362
Accounts receivable	16,000	15,012
Inventories	16,398	18,469
Prepaid expenses and other current assets	2,713	5,623
Total current assets	96,852	95,506
Property and equipment, net	10,186	9,973
Intangible assets, net	4,152	4,556
Other assets	671	331
Total assets	111,861	110,366
Current liabilities:
Accounts payable	5,115	7,059
Accrued liabilities	9,245	9,217
Total current liabilities	14,360	16,276
Other long-term liabilities	3,466	3,176
Total liabilities	17,826	19,452
Commitments and contingencies (Note 6)
Stockholders’ equity:
Additional paid-in capital	294,085	288,719
Accumulated other comprehensive loss	(175)	(96)
Accumulated deficit	(199,875)	(197,709)
Total stockholders’ equity	94,035	90,914
Total liabilities and stockholders’ equity	$ 111,861	$ 110,366