Note 3 - Valuation and Qualifying Accounts (Tables)

12 Months Ended

Mar. 31, 2021

Notes Tables

Valuation and Qualifying Accounts [Table Text Block]

	Year Ended March 31,
	2021			2020			2019
Allowance for doubtful accounts:
Balance at beginning of period	$	59		$	39		$	35
Provision for doubtful accounts		130			191			85
Write-off of uncollectible accounts receivable		(150	)		(171	)		(81	)
Balance at end of year	$	39		$	59		$	39