Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ 2,916	$ (1,213)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	1,946	1,950
Provision for losses on accounts receivable	40	125
Stock-based compensation	162	73
Loss on disposal of property and equipment	13	7
Changes in operating assets and liabilities:
Accounts receivable	(4,689)	(2,802)
Inventory	(5,127)	(1,069)
Prepaid expenses and other current assets	(1,058)	74
Other assets	(285)	(268)
Accounts payable	2,701	2
Accrued and other long-term liabilities	(1,366)	(1,477)
Customer advances	166	247
Deferred revenue	156	331
Non-current income taxes payable	255	274
Net cash used in operating activities	(4,170)	(3,746)
Cash flows from investing activities:
Purchases of property, equipment and intangibles	(3,390)	(715)
Proceeds from sale of property and equipment	0	6
Net cash used in investing activities	(3,390)	(709)
Cash flows from financing activities:
Principal payments on debt and capital leases	(29)	(325)
Payments of deferred offering costs	(521)	(8)
Proceeds from stock option exercises	61	61
Net cash used in financing activities	(489)	(272)
Effect of exchange rate changes on cash	(16)	141
Net decrease in cash and cash equivalents	(8,065)	(4,586)
Cash and cash equivalents, beginning of period	36,687	13,500
Cash and cash equivalents, end of period	28,622	8,914
Supplemental disclosures:
Cash paid for interest	252	459
Cash paid for income taxes	990	341
Accrued purchases of property, equipment and intangibles	1,380	291
Accrued deferred offering costs	$ 797	$ 26