Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net income	$ 98,650	$ 49,982	$ 17,034
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	10,818	9,939	7,880
Gain on sale of equipment		(168)
Deferred income taxes	20,257	4,685	3,304
Stock-based compensation expense	12,067	10,485	8,173
Provision for doubtful accounts			818
Provision for excess and obsolete inventory	3,755	3,696	2,794
Changes in operating assets and liabilities:
Accounts receivable	(18,146)	(1,393)	(6,002)
Inventories	(39,023)	(17,652)	(17,953)
Prepaid expenses and other current assets	(3,955)	(7,322)	(104)
Accounts payable and other current liabilities	22,046	18,062	(19,150)
Deferred revenue	45,385	(6,215)	6,672
Income taxes	253	332	(162)
Other assets and liabilities	(1,917)	5,272	(16,898)
Net cash provided by (used in) operating activities	150,190	69,703	(13,594)
Cash flows from investing activities
Proceeds from sale of equipment		168
Expenditures for property, plant and equipment and capitalized software	(8,718)	(7,434)	(11,969)
Net cash used in investing activities	(8,718)	(7,266)	(11,969)
Cash flows from financing activities
Net settlement on restricted stock grants	(6,564)	(3,915)	(1,632)
Repurchase of common stock	(49,992)	(7,501)	(17,744)
Proceeds from Employee Stock Purchase Plan	1,179	1,009	863
Principal payments on finance lease obligation	(763)	(399)
Proceeds from exercise of stock options	3,687	8,419	5,105
Net cash used in financing activities	(52,453)	(2,387)	(13,408)
Effect of exchange rate changes on cash and cash equivalents	2,429	(2,352)	603
Net increase (decrease) in cash, cash equivalents and restricted cash	91,448	57,698	(38,368)
Cash, cash equivalents and restricted cash at beginning of period	204,232	146,534	184,902
Cash, cash equivalents and restricted cash at end of period	295,680	204,232	146,534
Supplemental disclosure of cash flow information
Income taxes	1,500	876	1,028
Interest	$ 5,086	$ 5,156	$ 5,207