Valuation and Qualifying Accounts - Activity in the Company's valuation and qualifying accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Allowance for doubtful accounts:
Provision for doubtful accounts	$ 95	$ 56	$ 47
Allowance for Doubtful Accounts
Allowance for doubtful accounts:
Balance at beginning of period	5	5	6
Provision for doubtful accounts	95	56	47
Write-off of uncollectible accounts receivable	(93)	(56)	(48)
Balance at end of year	$ 7	$ 5	$ 5