Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013		Mar. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 15,289	$ 11,252		$ 10,036
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,466	1,065		845
Stock-based compensation	465	1,064		801
Excess tax benefit from stock-based compensation	(2,118)	(8,113)		(150)
Accretion of imputed interest on purchase of intangible asset	142	143		0
Change in fair value of convertible preferred stock warrant liability	0	13		1,208
Loss on disposal of property and equipment	61	46		0
Deferred taxes	493	177		442
Changes in operating assets and liabilities:
Accounts receivable	432	(7,580)	[1]	(3,114)	[1]
Inventory	(3,342)	(4,945)		(549)
Income tax receivable	588	3,853		(164)
Prepaid expenses, other current and non-current assets	775	1,496		109
Accounts payable	2,801	3,356		(9,499)
Related-party payable	0	(1,305)		1,299
Accrued expenses and other non-current liabilities	194	8,194	[1]	27	[1]
Net cash provided by operating activities	17,246	8,716		1,291
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(1,637)	(2,766)		(3,538)
Restricted cash	(300)	0		0
Net cash used in investing activities	(1,937)	(2,766)		(3,538)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from credit facility	8,432	23,737		72,389
Payments to credit facility	(15,439)	(29,526)		(59,593)
Proceeds from common shares issued in initial public offering, net of issuance costs	0	11,146		0
Dividends paid	0	0		(13,550)
Payments of initial public offering costs	0	0		(3,368)
Repurchase of common stock	0	(19,125)		0
Net repurchase of stock options	0	0		(602)
Excess tax benefit from stock-based compensation	2,118	8,113		150
Proceeds from exercises of stock options	1,958	4,073		50
Net cash used in financing activities	(2,931)	(1,582)		(4,524)
NET INCREASE (DECREASE) IN CASH	12,378	4,368		(6,771)
CASH—Beginning of year	4,930	562		7,333
CASH—End of year	17,308	4,930		562
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest	148	17		67
Cash paid for income taxes	5,611	247		6,153
NONCASH INVESTING AND FINANCING ACTIVITIES:
Conversion of convertible preferred stock into common stock	0	81,373		0
Deferred initial public offering costs funded through accounts payable and accrued expenses	0	0		1,975
Intangible asset acquired by financing transaction	$ 0	$ 0		$ 1,023

[1] Includes an immaterial reclassification between accounts receivable and accrued liabilities.