Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (14,772)	$ (951)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	1,522	1,062
Stock-based compensation	8,822	7,233
Deferred income taxes	1,839	0
Amortization of investment premium, net	33	44
Provision for doubtful accounts receivable	231	158
Provision for excess and obsolete inventory	153	253
Loss on disposal and write-off of property and equipment	22	0
Gain on foreign currency exchange rates	(1,501)	0
Changes in operating assets and liabilities:
Accounts receivable	(10,098)	(9,414)
Inventory	(521)	(2,994)
Prepaid expenses and other assets	702	707
Deferred revenue, net of deferred costs	12,336	2,645
Accounts payable, accrued and other liabilities	6,895	8,487
Net cash provided by operating activities	5,663	7,230
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of investments	(741)	(6,024)
Proceeds from sale of investments	8,683	0
Proceeds from maturity of investments	3,398	11,310
Purchase of property and equipment	(2,733)	(1,188)
Change in restricted cash	(421)	1
Net cash provided by investing activities	8,186	4,099
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments on capital leases	(62)	(59)
Proceeds from issuance of common stock upon exercise of stock options and from employee stock purchase program	1,801	2,816
Tax payments related to shares withheld for vested restricted stock units	(3,871)	(5,599)
Tax effect of employee stock plans	0	17
Net cash used in financing activities	(2,132)	(2,825)
Effect of exchange rate changes on cash and cash equivalents	(497)	153
NET INCREASE IN CASH AND CASH EQUIVALENTS	11,220	8,657
CASH AND CASH EQUIVALENTS—Beginning of period	35,710	28,649
CASH AND CASH EQUIVALENTS—End of period	$ 46,930	$ 37,306