Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net loss	$ (6,634)	$ (8,702)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	1,656	1,247
Stock-based compensation expense	4,429	2,175
Provision for doubtful accounts	201	161
Change in fair value of preferred stock warrant liability		735
Noncash interest expense		20
Loss from exit of facilities	129
Changes in operating assets and liabilities:
Accounts receivable	26,986	18,251
Inventories	(5,430)	5,712
Prepaid expenses and other current assets	(11,643)	(2,572)
Deferred cost of revenue	2,090	(425)
Other noncurrent assets	(353)	(2,949)
Accounts payable and accrued liabilities	(18,474)	(2,892)
Other long-term liabilities	(118)	3,797
Deferred revenue	(7,476)	11,681
Net cash provided by (used in) operating activities	(14,637)	26,239
Cash flows from investing activities:
Purchase of property and equipment	(3,407)	(1,560)
Net cash used in investing activities	(3,407)	(1,560)
Cash flows from financing activities:
Repayments of borrowings		(15,000)
Proceeds from exercise of stock options, net of repurchases	1,544	473
Net cash provided by (used in) financing activities	1,544	(14,527)
Net Increase (Decrease) In Cash	(16,500)	10,152
Cash—Beginning of period	177,250	34,562
Cash—End of period	160,750	44,714
Supplemental disclosures of cash flow information:
Cash paid for interest		136
Cash paid for income taxes	180	29
Supplemental disclosures of noncash investing and financing activities:
Unpaid portion of property and equipment purchases	$ 1,460	$ 1,166