CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities:
Net (loss) income	$ (5,086)	$ 6,472
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation and amortization	7,707	6,352
Stock-based compensation	3,195	2,731
Provision for bad debts	230	574
Loss on disposal of assets	122	305
Provision for excess and obsolete inventory	736	1,440
Deferred income tax expense (benefit)	168	(261)
Income tax benefit from exercise of stock options	0	(70)
Decrease (increase) in:
Accounts receivable	4,771	13,818
Inventories	(10,107)	(4,918)
Prepaid expenses and other current assets	(6,489)	2,115
(Decrease) increase in:
Accounts payable and accrued liabilities	1,610	(1,596)
Income taxes payable	(590)	522
Customer deposits	(163)	(870)
Unearned service revenues	(472)	1,114
Net cash (used in) provided by operating activities	(4,368)	27,728
Investing activities:
Proceeds from sale of short-term investments	21,000	0
Purchases of property and equipment	(3,669)	(2,580)
Payments for intangible assets	(645)	(712)
Acquisition of business	(5,496)	0
Net cash provided by (used in) investing activities	11,190	(3,292)
Financing activities:
Payments on capital leases	(4)	(4)
Income tax benefit from exercise of stock options	0	70
Proceeds from issuance of stock, net	284	513
Net cash provided by financing activities	280	579
Effect of exchange rate changes on cash and cash equivalents	4,323	1,170
Increase in cash and cash equivalents	11,425	26,185
Cash and cash equivalents, beginning of period	106,169	107,356
Cash and cash equivalents, end of period	$ 117,594	$ 133,541