Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net income	$ 33,372	$ 50,867	$ 63,655
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	40,488	32,594	30,864
Stock-based compensation expense	19,095	14,673	10,781
Deferred taxes	339	7,577	6,106
Amortization of marketable securities	0	415	5
Realized loss on available-sale-securities	567	0	0
Changes in fair value of contingent consideration	(13,253)	0	0
Other	275	(336)	391
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(20,112)	(91)	1,848
Inventories	(2,390)	(662)	60
Prepaid expenses and other	64	(1,680)	545
Income taxes	(774)	(1,960)	6,555
Accounts payable	4,654	1,492	(719)
Accrued liabilities and other	(7,083)	4,080	(4,039)
Net cash provided by operating activities	55,242	106,969	116,052
Investing activities
Purchases of property, equipment and other capital assets	(34,209)	(47,010)	(62,230)
Cash used for acquisitions, net of cash acquired	(127,413)	0	0
Purchases of other assets and investments	0	(3,000)	(4,000)
Purchases of marketable securities	(16,159)	(113,200)	(46,403)
Proceeds from sales of marketable securities	64,913	0	0
Proceeds from maturities of marketable securities	18,204	67,737	68,330
Net cash used in investing activities	(94,664)	(95,473)	(44,303)
Financing activities
Proceeds from exercises of stock options	5,862	7,557	4,391
Purchases of shares withheld for tax obligations	(4,225)	(3,443)	(2,487)
Repurchases of common stock	(23,279)	(14,686)	(33,521)
Principal repayments of finance lease obligations	(552)	(154)	0
Other	4	0	0
Net cash used in financing activities	(22,198)	(10,726)	(31,617)
Effect of exchange rate changes on cash and cash equivalents	(54)	1,608	47
Net (decrease) increase in cash and cash equivalents	(61,674)	2,378	40,179
Cash and cash equivalents, beginning of period	127,603	125,225	85,046
Cash and cash equivalents, end of period	65,929	127,603	125,225
Supplemental cash flow disclosure
Cash paid for interest	28	23	14
Cash paid for taxes	$ 7,583	$ 5,650	$ 4,002