Investment Securities (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019
Total available-for-sale debt securities and equity securities
Amortized Cost	$ 15,002		$ 15,002		$ 33,240
Gross Unrealized Gains	104		104		222
Gross Unrealized Losses					(2)
Fair Value	15,106		15,106		33,460
Proceeds from sales or maturities of available-for-sale investment and equity securities
Proceeds from sales or maturities of available-for-sale investment securities and equity securities	18,423	$ 31,279	38,240	$ 60,571
Gross gains	212	261	440	386
Gross losses		(14)		(32)
Net realized gains on sales of available-for-sale investment securities and equity securities	212	$ 247	440	$ 354
Corporate Debt Securities | Current
Available-for-sale debt securities
Amortized Cost					2,779
Gross Unrealized Gains					1
Gross Unrealized Losses					(2)
Fair Value					2,778
Preference shares | Noncurrent
Available-for-sale debt securities
Amortized Cost	185		185		188
Fair Value	185		185		188
Agency And Short Term Notes | Current
Available-for-sale debt securities
Amortized Cost					1,492
Gross Unrealized Gains					1
Fair Value					1,493
Time Deposits | Current
Available-for-sale debt securities
Amortized Cost	7,079		7,079		15,861
Fair Value	7,079		7,079		15,861
Mutual funds | Current
Equity securities
Amortized Cost	7,737		7,737		12,912
Gross Unrealized Gains	92		92		94
Fair Value	7,829		7,829		13,006
Equity Shares/ Options | Noncurrent
Equity securities
Amortized Cost	1		1		8
Gross Unrealized Gains	12		12		126
Fair Value	$ 13		$ 13		$ 134