Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income	$ 19,865	$ 14,582
Adjustments to reconcile net income to cash flows:
Depreciation and amortization	7,185	5,578
Non-cash deferred revenue	(3,711)	(2,310)
Increase in inventory reserve	688	1,936
Unrealized loss/(gain) on foreign currency contracts	4	(1,006)
Stock based compensation	1,786	1,535
Deferred income tax provision	634	3,911
Other	(341)	238
Changes in assets and liabilities:
Trade receivables	43,313	45,861
Inventories	(28,246)	(21,009)
Prepaid expenses and other current assets	1,521	(3,993)
Accounts payable and other current liabilities	(9,982)	4,397
Deferred revenue and advance payments	1,450	39,926
Other non-current assets and liabilities	407	147
Discontinued operations:
Non-cash adjustments to net income	1,923
Net cash (used in)/provided by discontinued operations	(511)	382
Net cash provided by operating activities	35,985	90,175
Cash flows from investing activities:
Capital expenditures	(12,172)	(19,840)
Other		13
Net cash used in investing activities	(12,172)	(19,827)
Cash flows from financing activities:
Repayment of debt		(30,000)
Proceeds from stock options exercised	725	420
Other		4
Net cash provided by/(used in) financing activities	725	(29,576)
Effect of exchange rate changes on cash and cash equivalents	495	851
Net increase in cash and cash equivalents	25,033	41,623
Cash and cash equivalents at beginning of period	74,141	43,974
Cash and cash equivalents at end of period	$ 99,174	$ 85,597