CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 13,054	$ 16,210
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	45,010	32,779
Loss on sales and/or abandonment of property and equipment	803	371
Amortization of right-of-use operating lease assets	5,874
Write-off of patents and intangible assets	594	86
Acquired in-process research and development	525	306
Amortization of deferred credits	(70)	(71)
Amortization of long-term debt issuance costs	402	402
Stock-based compensation expense	4,289	2,821
Changes in operating assets and liabilities, net of effects from acquisitions:
Trade receivables	(21,206)	(27,947)
Other receivables	427	966
Inventories	(5,138)	(7,189)
Prepaid expenses and other current assets	(1,052)	(3,105)
Prepaid income taxes	(45)	(100)
Income tax refund receivables	(3,980)	(1,146)
Other assets	(2,845)	(751)
Trade payables	1,338	15,767
Accrued expenses	1,925	7,467
Income taxes payable	(2,059)	(2,076)
Deferred compensation payable	1,518	438
Operating lease liabilities	(5,882)
Other long-term obligations	2,208	(179)
Total adjustments	22,636	18,839
Net cash provided by operating activities	35,690	35,049
Capital expenditures for:
Property and equipment	(35,959)	(31,559)
Intangible assets	(1,607)	(1,755)
Proceeds from the sale of property and equipment	22	4
Issuance of note receivable	0	(10,500)
Cash paid in acquisitions, net of cash acquired	(37,256)	(118,654)
Net cash used in investing activities	(74,800)	(162,464)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	3,374	3,251
Proceeds from issuance of long-term debt	125,746	320,827
Payments on long-term debt	(120,746)	(185,827)
Contingent payments related to acquisitions	(611)	(130)
Net cash provided by financing activities	7,763	138,121
EFFECT OF EXCHANGE RATES ON CASH	(830)	470
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(32,177)	11,176
CASH AND CASH EQUIVALENTS:
Beginning of period	67,359	32,336
End of period	35,182	43,512
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Interest (net of capitalized interest of $540 and $314, respectively)	5,794	5,714
Income taxes	8,856	5,141
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES
Property and equipment purchases in accounts payable	3,331	3,943
Acquisition purchases in accrued expenses and other long-term obligations	8,400	0
Merit common stock surrendered (0 and 32 shares, respectively) in exchange for exercise of stock options	0	$ 1,684
Right-of-use operating lease assets obtained in exchange for operating lease liabilities	$ 2,927