Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income	$ 25,196	$ 22,806
Adjustments to reconcile net income to net cash from operating activities:
Provision for credit losses on accounts receivable	965	460
Reserve for product returns	1,000	(44)
Recovery of credit losses on notes receivable	(382)	(3,319)
Amortization on patents and tooling	401	334
Amortization and depreciation	13,145	10,366
Amortization of debt issuance costs	54	54
Amortization of operating leases	4,234	3,638
Deferred income taxes	(2,526)	(627)
Change in fair value of contingent liability	(2,289)	0
Stock-based compensation	13,453	9,686
Acquired in-process research and development	3,297	0
Changes in operating assets and liabilities:
Accounts receivable	(2,549)	(10,927)
Inventory	(16,238)	(905)
Other current and non-current assets	(3,270)	(2,161)
Accounts payable, accrued expenses and other current liabilities	17,332	(2,528)
Deferred revenue	1,039	(196)
Operating lease liabilities	(4,728)	(3,928)
Other liabilities	(86)	158
Cash flows from operating activities	48,048	22,867
Cash flows used in investing activities:
Additions to property and equipment	(7,116)	(5,708)
Purchases of in-process research and development	(3,297)	0
Issuances or purchases of notes receivable	0	(20,061)
Receipt of payment on notes receivable	2,007	7,400
Purchases of patents and patent licenses	(900)	0
Cash flows used in investing activities	(9,306)	(18,369)
Cash flows from financing activities:
Proceeds from credit facility	50,000	0
Repayments of credit facility	(1,000)	(2,000)
Payments of deferred consideration for business acquisitions	(819)	0
Purchases of treasury stock	(5,149)	0
Issuances of common stock from equity-based plans	4,424	2,292
Cash flows from financing activities	47,456	292
Net increase in cash and cash equivalents	86,198	4,790
Cash and cash equivalents at beginning of the period	119,629	146,061
Cash and cash equivalents at end of the period	$ 205,827	$ 150,851