Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 15,649	$ 26,136
Short-term investments	44,860	51,419
Accounts receivable, net	16,301	19,564
Inventory, net	19,065	20,057
Prepaid expenses and other	5,786	4,745
Total current assets	101,661	121,921
Restricted cash	0	143
Property and equipment, net	14,450	14,057
Other assets	686	641
Total assets	116,797	136,762
Current liabilities:
Accounts payable	4,920	4,092
Accrued liabilities	2,505	4,507
Accrued compensation and other employee benefits	5,884	8,634
Customer deposits	6,756	8,945
Deferred revenue, current portion	10,312	9,229
Deferred rent, current portion	547	512
Total current liabilities	30,924	35,919
Deferred revenue, net of current portion	3,151	3,304
Deferred rent and other long-term liabilities	8,384	8,499
Long-term debt, net of debt issuance costs	49,325	48,931
Total liabilities	91,784	96,653
Commitment and contingencies
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; 25,696 and 25,421 shares issued and outstanding at March 31, 2018 and December 31, 2017, respectively	3	2
Additional paid-in capital	358,180	353,308
Accumulated other comprehensive loss	(112)	(99)
Accumulated deficit	(333,058)	(313,102)
Total stockholders’ equity	25,013	40,109
Total liabilities and stockholders’ equity	$ 116,797	$ 136,762