CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 8,842	$ 8,040
Short-term investments	58,507	48,362
Accounts receivable	15,781	15,012
Inventories	15,005	18,469
Prepaid expenses and other current assets	2,413	5,623
Total current assets	100,548	95,506
Property and equipment, net	10,423	9,973
Intangible assets, net	3,950	4,556
Other assets	679	331
Total assets	115,600	110,366
Current liabilities:
Accounts payable	5,644	7,059
Accrued liabilities	10,718	9,217
Total current liabilities	16,362	16,276
Other long-term liabilities	4,274	3,176
Total liabilities	20,636	19,452
Commitments and contingencies (Note 6)
Stockholders’ equity:
Additional paid-in capital	297,024	288,719
Accumulated other comprehensive loss	(120)	(96)
Accumulated deficit	(201,940)	(197,709)
Total stockholders’ equity	94,964	90,914
Total liabilities and stockholders’ equity	$ 115,600	$ 110,366