Note 4 - Fair Value - Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands		Jun. 30, 2016	Mar. 31, 2016
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets
Money market funds	[1],[2]	$ 89,440	$ 115,974
Marketable equity securities	[2],[3]	1,879	1,749
Auction rate preferred securities	[2],[3]
Total Assets Measured at Fair Value	[2]	91,319	117,723
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets
Money market funds	[1],[2]
Marketable equity securities	[2],[3]
Auction rate preferred securities	[2],[3]	350	350
Total Assets Measured at Fair Value	[2]	350	350
Fair Value, Measurements, Recurring [Member]
Assets
Money market funds	[1],[2]	89,440	115,974
Marketable equity securities	[2],[3]	1,879	1,749
Auction rate preferred securities	[2],[3]	350	350
Total Assets Measured at Fair Value	[2]	91,669	118,073
Marketable equity securities		1,879	1,749
Auction rate preferred securities		$ 350	$ 350

[1] Included in "Cash and cash equivalents" on our unaudited condensed consolidated balance sheets.

[2] We did not have any recurring fair value measurements of assets or liabilities whose fair value was measured using significant unobservable inputs.

[3] Included in "Other assets" on our unaudited condensed consolidated balance sheets.