CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating activities:
Net income (loss)	$ 8,859	$ (1,709)
Adjustments required to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	663	621
Bad debt expense	(37)	31
Stock-based compensation	4,799	4,290
Write-down of inventory	299	206
Excess tax benefit from stock-based awards	(81)
Deferred tax provision	5,805	225
Change in fair value of contingent consideration	151
Changes in assets and liabilities:
Accounts receivable	(2,456)	1,548
Inventories	(4,549)	(234)
Prepaid expenses and other assets	463	(255)
Accounts payable	(1,767)	(1,049)
Accrued expenses and other long-term liabilities	(2,063)	(919)
Deferred revenue	828	435
Net cash provided by operating activities	10,914	3,190
Investing activities:
Purchases of marketable securities	(42,661)	(24,524)
Proceeds from the sale and maturity of marketable securities	50,263	35,730
Purchases of property and equipment	(1,863)	(380)
Net cash provided by investing activities	5,739	10,826
Financing activities:
Proceeds from the exercise of stock options	4,589	820
Excess tax benefit from stock-based awards	81
Taxes paid related to net share settlement of vesting of stock awards	(3,465)	(1,013)
Proceeds from the issuance of stock under employee stock purchase plan	5
Net cash provided by (used for) financing activities	1,210	(193)
Effect of exchange rate changes on cash	167	1
Net increase in cash and cash equivalents	18,030	13,824
Cash and cash equivalents at beginning of period	22,401	20,916
Cash and cash equivalents at end of period	40,431	34,740
Supplemental disclosure of cash flow information:
Cash paid for income taxes	274	172
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment in accounts payable and accrued expenses	$ 123	$ 215