Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 26,136	$ 20,583
Short-term investments	51,419	53,453
Accounts receivable, net	19,564	22,193
Inventory, net	20,057	13,812
Prepaid expenses and other current assets	4,745	3,744
Total current assets	121,921	113,785
Restricted cash	143	143
Property and equipment, net	14,057	12,158
Other assets	641	287
Total assets	136,762	126,373
Current liabilities:
Accounts payable	4,092	4,935
Accrued liabilities	4,507	3,494
Employee-related Liabilities, Current	8,634	8,240
Customer Deposits, Current	8,945	610
Deferred revenue, current portion	9,229	19,033
Deferred rent, current portion	512	13
Lease financing obligations, current portion	0	58
Total current liabilities	35,919	36,383
Deferred revenue, net of current portion	3,304	22,664
Deferred rent and other liabilities, net of current portion	8,499	7,655
Long-term debt and lease financing obligations, net of current portion and debt issuance costs	48,931	47,366
Total liabilities	96,653	114,068
Commitments and contingencies (Note 13)
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; 25,421 and 21,528 shares issued and outstanding at December 31, 2017 and 2016, respectively	2	2
Additional paid-in-capital	353,308	281,900
Other comprehensive loss	(99)	(57)
Accumulated deficit	(313,102)	(269,540)
Total stockholders’ equity	40,109	12,305
Total liabilities and stockholders’ equity	$ 136,762	$ 126,373