Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities
Net income	$ 11,221	$ 6,062
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	2,363	1,615
Deferred income taxes	899	582
Stock-based compensation expense	1,724	1,672
Provision for excess and obsolete inventory	802	607
Changes in operating assets & liabilities:
Accounts receivable	19,223	7,642
Inventories	1,924	(6,171)
Prepaid expenses and other current assets	(4,435)	(1,174)
Accounts payable and other current liabilities	1,689	(16,911)
Deferred revenue	4,859	(2,098)
Income taxes	53	32
Other assets and liabilities	(645)	(4,207)
Net cash provided by (used in) operating activities	39,677	(12,349)
Cash flows from investing activities
Expenditures for property, plant and equipment and capitalized software	(1,290)	(4,255)
Net cash used in investing activities	(1,290)	(4,255)
Cash flows from financing activities
Net settlement on restricted stock grants	(1,162)	(281)
Repurchase of common stock	(7,501)
Proceeds from Employee Stock Purchase Plan	19
Proceeds from exercise of stock options	4,499	1,828
Net cash (used in) provided by financing activities	(4,145)	1,547
Effect of exchange rate changes on cash and cash equivalents	640	123
Net increase (decrease) in cash, cash equivalents and restricted cash	34,882	(14,934)
Cash, cash equivalents and restricted cash at beginning of period	146,534	184,902
Cash, cash equivalents and restricted cash at end of period	$ 181,416	$ 169,968