Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities
Net income	$ 24,523	$ 6,618
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	4,829	3,600
Deferred income taxes	3,035	1,341
Stock-based compensation expense	4,806	3,989
Provision for excess and obsolete inventory	1,708	1,329
Changes in operating assets & liabilities:
Accounts receivable	18,752	16,346
Inventories	(9,123)	(11,161)
Prepaid expenses and other current assets	(4,206)	(433)
Accounts payable and other current liabilities	11,808	(21,559)
Deferred revenue	1,167	(8,498)
Income taxes	5	(129)
Other assets and liabilities	(729)	(11,769)
Net cash provided by (used in) operating activities	56,575	(20,326)
Cash flows from investing activities
Expenditures for property, plant and equipment and capitalized software	(2,975)	(8,757)
Net cash used in investing activities	(2,975)	(8,757)
Cash flows from financing activities
Net settlement on restricted stock grants	(3,860)	(1,591)
Repurchase of common stock	(7,501)	(14,035)
Proceeds from Employee Stock Purchase Plan	509	407
Principal payments on finance lease obligation	(108)
Proceeds from exercise of stock options	7,282	2,396
Net cash used in financing activities	(3,678)	(12,823)
Effect of exchange rate changes on cash and cash equivalents	560	168
Net increase (decrease) in cash, cash equivalents and restricted cash	50,482	(41,738)
Cash, cash equivalents and restricted cash at beginning of period	146,534	184,902
Cash, cash equivalents and restricted cash at end of period	$ 197,016	$ 143,164