Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Allowance for doubtful accounts:
Balance at beginning of period	$ 8	$ 7	$ 5
Provision for doubtful accounts	260	94	95
Write-off of uncollectible accounts receivable	(255)	(93)	(93)
Balance at end of year	$ 13	$ 8	$ 7