Note 3 - Fair Value (Tables)

6 Months Ended

Sep. 30, 2017

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	September 30, 2017 (1)						March 31, 2017 (1)
			Fair Value Measured at						Fair Value Measured at
			Reporting Date Using						Reporting Date Using
Description	Total		Level 1		Level 2		Total		Level 1		Level 2
	(unaudited)						(unaudited)
Money market funds (2)	$	96,780	$	96,780	$	-	$	90,752	$	90,752	$	-
Marketable equity securities (3)		1,649		1,649		-		1,771		1,771		-
Auction rate preferred securities (3)		350		-		350		350		-		350
Total assets measured at fair value	$	98,779	$	98,429	$	350	$	92,873	$	92,523	$	350