CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Operating activities:
Net income	$ 37,374	$ 12,910
Adjustments required to reconcile net income to net cash provided by operating activities:
Depreciation expense	2,463	1,406
Bad debt expense	(42)	(31)
Stock-based compensation	8,656	8,397
Write-down of inventory	510	708
Excess tax benefit from stock-based awards		(1,041)
Deferred tax provision	(3,830)	7,000
Change in fair value of contingent consideration	265	176
Changes in assets and liabilities:
Accounts receivable	795	1,517
Inventories	(1,302)	(3,393)
Prepaid expenses and other assets	(915)	7
Accounts payable	(4,391)	(145)
Accrued expenses and other liabilities	(2,436)	(952)
Deferred revenue	(853)	(179)
Net cash provided by operating activities	36,294	26,380
Investing activities:
Purchases of marketable securities	(73,626)	(67,318)
Proceeds from the sale and maturity of marketable securities	66,622	47,090
Purchase of other investment	(400)
Purchases of property and equipment	(9,804)	(5,099)
Net cash used for investing activities	(17,208)	(25,327)
Financing activities:
Proceeds from the exercise of stock options	3,555	2,770
Excess tax benefit from stock-based awards		1,041
Taxes paid related to net share settlement of vesting of stock awards	(17,805)	(15,033)
Principal payments on capital lease obligation	(184)
Net cash used for financing activities	(14,434)	(11,222)
Effect of exchange rate changes on cash	278	212
Net increase in cash and cash equivalents	4,930	(9,957)
Cash and cash equivalents at beginning of period	39,040	48,231
Cash and cash equivalents at end of period	43,970	38,274
Supplemental disclosure of cash flow information:
Cash paid for income taxes	479	420
Cash paid for interest on capital lease obligation	130
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment in accounts payable and accrued expenses	$ 1,872	$ 996