Certain Financial Statement Information Fair Value (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Mar. 31, 2014
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	$ 83,023		$ 106,583
Cash, cash equivalents and available-for-sale investments measured at fair value on recurring basis	83,023		106,583
Level 1 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash, cash equivalents and available-for-sale investments measured at fair value on recurring basis	66,846		90,740
Level 2 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash, cash equivalents and available-for-sale investments measured at fair value on recurring basis	16,177		15,843
Level 3 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash, cash equivalents and available-for-sale investments measured at fair value on recurring basis	0		0
Cash [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash and cash equivalents measured at fair value on a recurring basis	40,828		65,867
Cash [Member] | Level 1 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash and cash equivalents measured at fair value on a recurring basis	40,828		65,867
Cash [Member] | Level 2 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash and cash equivalents measured at fair value on a recurring basis	0		0
Cash [Member] | Level 3 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash and cash equivalents measured at fair value on a recurring basis	0		0
Cash equivalents [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash and cash equivalents measured at fair value on a recurring basis	9,252		5,672
Cash equivalents [Member] | Level 1 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash and cash equivalents measured at fair value on a recurring basis	9,252		5,672
Cash equivalents [Member] | Level 2 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash and cash equivalents measured at fair value on a recurring basis	0		0
Cash equivalents [Member] | Level 3 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Cash and cash equivalents measured at fair value on a recurring basis	0		0
U.S Treasury securities and agency bonds [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	1,475		2,838
U.S Treasury securities and agency bonds [Member] | Level 1 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	1,475		2,838
U.S Treasury securities and agency bonds [Member] | Level 2 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	0		0
U.S Treasury securities and agency bonds [Member] | Level 3 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	0		0
Corporate bonds [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	10,916		10,627
Corporate bonds [Member] | Level 1 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	0		0
Corporate bonds [Member] | Level 2 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	10,916		10,627
Corporate bonds [Member] | Level 3 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	0		0
Mortgage-backed and asset-backed securities [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	1,903	[1]	2,074	[1]
Mortgage-backed and asset-backed securities [Member] | Level 1 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	0		0
Mortgage-backed and asset-backed securities [Member] | Level 2 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	1,903		2,074
Mortgage-backed and asset-backed securities [Member] | Level 3 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	0		0
Closed-end bond funds [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	15,291		16,363
Closed-end bond funds [Member] | Level 1 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	15,291		16,363
Closed-end bond funds [Member] | Level 2 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	0		0
Closed-end bond funds [Member] | Level 3 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	0		0
Preferred stock [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	3,358		3,142
Preferred stock [Member] | Level 1 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	0		0
Preferred stock [Member] | Level 2 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	3,358		3,142
Preferred stock [Member] | Level 3 [Member]
Schedule of Cash, Cash Equivalents and Available-For-Sale Investments by Type of Instruments Measured at Fair Value on Recurring Basis
Available-for-sale securities measured at fair value on a recurring basis	$ 0		$ 0

[1] At December 31, 2014 and March 31, 2014, approximately $1.0 million and $1.1 million of the estimated fair value presented were mortgage-backed securities, respectively.