CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ (3,154)	$ 6,195
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	23,320	22,348
Loss on sales and/or abandonment of property and equipment	37	288
Write-off of certain intangible assets and other long-term assets	3,925
Acquired in-process research and development		25
Amortization of right-of-use operating lease assets	3,134	2,964
Fair value adjustments to contingent consideration	4,897	775
Amortization of deferred credits	(35)	(35)
Amortization of long-term debt issuance costs	151	201
Stock-based compensation expense	2,777	1,766
Changes in operating assets and liabilities, net of effects from acquisitions:
Trade receivables	3,445	(11,557)
Other receivables	613	1,090
Inventories	(4,983)	(1,340)
Prepaid expenses and other current assets	(3,126)	19
Prepaid income taxes		(53)
Income tax refund receivables	(2,475)	(442)
Other assets	(577)	(2,092)
Trade payables	4,340	(878)
Accrued expenses	(1,621)	(2,976)
Income taxes payable	2,109	(879)
Deferred compensation payable	(789)	1,261
Operating lease liabilities	(2,945)	(3,054)
Other long-term obligations	(179)	(121)
Total adjustments	32,018	7,310
Net cash provided by operating activities	28,864	13,505
Capital expenditures for:
Property and equipment	(13,950)	(18,255)
Intangible assets	(1,062)	(853)
Proceeds from the sale of property and equipment		3
Cash received for settlement of current note receivable	250
Cash paid in acquisitions, net of cash acquired		(1,942)
Net cash used in investing activities	(14,762)	(21,047)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	1,261	1,733
Proceeds from issuance of long-term debt	30,665	43,119
Payments on long-term debt	(24,540)	(54,119)
Contingent payments related to acquisitions	(12,754)	(554)
Payment of taxes related to an exchange of common stock	(866)
Net cash used in financing activities	(6,234)	(9,821)
EFFECT OF EXCHANGE RATES ON CASH	(2,108)	(474)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	5,760	(17,837)
CASH AND CASH EQUIVALENTS:
Beginning of period	44,320	67,359
End of period	50,080	49,522
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Interest (net of capitalized interest of $392 and $241, respectively)	3,198	2,721
Income taxes	1,637	1,934
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES
Property and equipment purchases in accounts payable	5,383	4,588
Current note receivable converted to equity investment	899
Right-of-use operating lease assets obtained in exchange for operating lease liabilities	$ 2,800	$ 1,162