Certain Financial Statement Information Fair Value (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Mar. 31, 2013
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 short term investments, measured at fair value on a recurring basis	$ 74,284		$ 85,476
Cash, cash equivalents and available-for-sale investments measured at fair value on recurring basis	74,284		85,476
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	51,043		57,625
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	23,241		27,851
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	19,716		8,529
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	19,716		8,529
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	3,914		10,536
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	3,914		9,508
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		1,028
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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	11,751		12,373
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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	11,596		12,373
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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	155		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
Cash, cash equivalents and short term investments, 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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	15,534		15,628
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
Cash, cash equivalents and short term investments, 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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	15,534		15,628
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
Cash, cash equivalents and short term investments, 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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	4,268	[1]	4,003	[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
Cash, cash equivalents and short term investments, 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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	4,268		4,003
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
Cash, cash equivalents and short term investments, 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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	15,817		27,215
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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	15,817		27,215
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
Cash, cash equivalents and short term investments, 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
Cash, cash equivalents and short term investments, 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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	3,284		7,192
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
Cash, cash equivalents and short term investments, 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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	3,284		7,192
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
Cash, cash equivalents and short term investments, measured at fair value on a recurring basis	$ 0		$ 0

[1] At December 31, 2013 and March 31, 2013, approximately $1.1 million and $1.4 million of the estimated fair value presented were mortgage-backed securities, respectively.