Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss	$ (19,021)	$ (15,651)
Adjustments to reconcile net loss to net cash provided by operating activities:
Change in allowance for doubtful accounts	4,386	1,766
Change in the fair value of acquisition-related contingent consideration		(2,063)
Amortization and write-off of deferred financing fees	582	582
Depreciation and amortization	38,427	37,998
Stock-based compensation	4,475	5,406
Foreign exchange loss (gain)	835	(194)
Deferred income taxes	(1,194)	(1,097)
Other	1,665	1,971
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	2,591	(5,972)
Inventories	5,703	(3,973)
Prepaid expenses and other assets	3,095	(3,338)
Accounts payable and accrued liabilities	1,344	6,960
Deferred revenue	(1,328)	(348)
Other liabilities	(2,123)	(1,246)
Net cash provided by operating activities	39,437	20,801
Cash flows from investing activities:
Capital expenditures	(14,710)	(16,234)
Capital expenditures associated with the subscription model	(894)
Net cash used in investing activities	(15,604)	(16,234)
Cash flows from financing activities:
Purchases of common stock under share repurchase program	(2,527)	(7,875)
Payments under revolving credit facility	(15,000)
Proceeds under revolving credit facility	15,000
Payments under the Paycheck Protection Program	(7,588)
Proceeds under the Paycheck Protection Program	7,588
Proceeds from issuance of common stock under employee stock purchase plan	430	604
Net cash used in financing activities	(2,097)	(7,271)
Effect of exchange rate changes on cash and cash equivalents	352	(158)
Net increase in cash and cash equivalents	22,088	(2,862)
Beginning of period	54,258	53,766
End of period	76,346	50,904
Cash paid for:
Interest	10,136	10,000
Income taxes	3,826	2,439
Noncash investing and financing activities:
Capital expenditures incurred not yet paid	1,177	785
Stock-based compensation related to capital expenditures	$ 377	539
Series A convertible preferred stock dividend paid in kind		12
Common stock issued as payment for MPUs		$ 502