Consolidated Balance Sheets - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 20,583,000	$ 21,856,000
Short-term investments	53,453,000	27,188,000
Accounts receivable, net	22,193,000	19,725,000
Inventory	13,812,000	10,138,000
Prepaid expenses and other current assets	3,744,000	3,886,000
Total current assets	113,785,000	82,793,000
Restricted cash	143,000	143,000
Deferred offering costs	0	181,000
Property and equipment, net	12,158,000	9,414,000
Other assets	287,000	338,000
Total assets	126,373,000	92,869,000
Current liabilities:
Accounts payable	4,935,000	3,243,000
Accrued liabilities	12,344,000	12,181,000
Deferred revenue, current portion	19,033,000	5,261,000
Deferred rent, current portion	13,000	0
Lease financing obligations, current portion	58,000	226,000
Total current liabilities	36,383,000	20,911,000
Deferred revenue, net of current portion	22,664,000	6,486,000
Deferred rent and other liabilities, net of current portion	7,655,000	4,257,000
Long-term debt and lease financing obligations, net of current portion and debt issuance costs	47,366,000	41,000,000
Total liabilities	114,068,000	72,654,000
Commitments and contingencies (Note 15)
Stockholders’ equity
Preferred stock, $0.0001 par value, 15,000 shares authorized; none issued	0	0
Common stock, $0.0001 par value, 150,000 shares authorized; 21,528 and 19,570 shares issued and outstanding at December 31, 2016 and 2015, respectively	2,000	2,000
Additional paid-in-capital	281,900,000	242,693,000
Other comprehensive loss	(57,000)	(29,000)
Accumulated deficit	(269,540,000)	(222,451,000)
Total stockholders’ equity	12,305,000	20,215,000
Total liabilities and stockholders’ equity	$ 126,373,000	$ 92,869,000