CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net loss	$ (3,221)	$ (14,823)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	3,190	3,759
Stock-based compensation	2,094	2,178
Provisions for bad debts, net of recoveries	(89)	(15)
Loss on disposal of assets	20	10
Provision for excess and obsolete inventory	1,404	204
Deferred income tax benefit	(1,612)	(2,326)
Decrease (Increase) in:
Accounts receivable	3,676	16,084
Inventories	(3,999)	1,795
Prepaid expenses and other current assets	(1,346)	7,408
(Decrease) Increase in:
Accounts payable and accrued liabilities	(9,823)	4,756
Income taxes payable	(1,153)	(1,389)
Customer deposits	896	(961)
Unearned service revenues	(323)	(365)
Net cash (used in) provided by operating activities	(10,286)	16,315
Investing activities:
Purchases of property and equipment	(1,547)	(757)
Proceeds from sale of investments	0	9,000
Payments for intangible assets	(890)	(435)
Net cash (used in) provided by investing activities	(2,437)	7,808
Financing activities:
Payments on finance leases	(86)	(82)
Payments for taxes related to net share settlement of equity awards	(3,336)	(1,581)
Proceeds from issuance of stock related to stock option exercises	5,118	2,802
Net cash provided by financing activities	1,696	1,139
Effect of exchange rate changes on cash and cash equivalents	(4,649)	(1,656)
Increase in cash and cash equivalents	(15,676)	23,606
Cash and cash equivalents, beginning of period	185,633	133,634
Cash and cash equivalents, end of period	$ 169,957	$ 157,240