CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net income	$ 14,907us-gaap_NetIncomeLoss	$ 5,641us-gaap_NetIncomeLoss	$ 4,076us-gaap_NetIncomeLoss
Adjustments to reconcile net income to net cash provided by operating activities:
Write-off of engineering project development qualification units	82	399	398
Shipped qualification assets	142bzc_ShippedQualificationAssets	747bzc_ShippedQualificationAssets	124bzc_ShippedQualificationAssets
Depreciation and amortization	2,050	1,699	1,475
Non-cash interest expense	290bzc_NoncashInterestExpenses	333bzc_NoncashInterestExpenses	393bzc_NoncashInterestExpenses
Stock based compensation	1,043us-gaap_ShareBasedCompensation	672us-gaap_ShareBasedCompensation	813us-gaap_ShareBasedCompensation
Provision for losses on accounts receivable	365us-gaap_ProvisionForDoubtfulAccounts	31us-gaap_ProvisionForDoubtfulAccounts	17us-gaap_ProvisionForDoubtfulAccounts
Deferred taxes-net	(3,175)	2,127	2,462
Changes in assets and liabilities:
(Increase) decrease in accounts receivable and other receivables	1,492	(8,267)	3,431
(Increase) decrease in inventories	(518)us-gaap_IncreaseDecreaseInInventories	(1,119)us-gaap_IncreaseDecreaseInInventories	(3,816)us-gaap_IncreaseDecreaseInInventories
(Increase) decrease in other assets	(80)	(228)	(597)
Increase (decrease) in accounts payable	(921)	1,916	(253)
Increase (decrease) in accrued income taxes	2,566	(383)	398
Increase (decrease) in other liabilities	(1,342)	(2,597)	(1,427)
Net cash provided by operating activities	16,901	971	7,494
Cash flows from investing activities:
Capital expenditures	(735)	(997)	(458)
Capitalized qualification units and pre-qualification assets	(43)	(1,520)	(2,513)
Net cash used in investing activities	(778)	(2,517)	(2,971)
Cash flows from financing activities:
Payments on long-term debt			(10,679)us-gaap_RepaymentsOfLongTermDebt
Payment of debt issue costs		(33)us-gaap_PaymentsOfDebtIssuanceCosts
Exercise of stock options	662	912	161
Net cash provided by (used in) financing activities	662	879	(10,518)
Increase (decrease) in cash	16,785	(667)	(5,995)
Cash at beginning of year	6,021	6,688	12,683
Cash at end of year	22,806	6,021	6,688
Supplemental information:
Interest payments	25us-gaap_InterestPaid	39us-gaap_InterestPaid	92us-gaap_InterestPaid
Income tax payments	270us-gaap_IncomeTaxesPaid	1,909us-gaap_IncomeTaxesPaid	806us-gaap_IncomeTaxesPaid
Non-cash financing activity for stock option exercise			$ 122

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