Certain Financial Statement Information Short Term Investments Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Mar. 31, 2015
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	$ 76,616	$ 75,358
Cash, cash equivalents and available-for-sale investments measured at fair value on recurring basis	76,616	75,358
Level 1
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	65,672	64,516
Level 2
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	10,944	10,842
Level 3
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
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	35,209	33,936
Cash | Level 1
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	35,209	33,936
Cash | Level 2
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 | Level 3
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
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	9,081	2,559
Cash equivalents | Level 1
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	9,081	2,559
Cash equivalents | Level 2
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 | Level 3
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
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	985	1,230
U.S Treasury securities and agency bonds | Level 1
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	985	1,230
U.S Treasury securities and agency bonds | Level 2
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 | Level 3
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
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	10,922	10,794
Corporate bonds | Level 1
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 | Level 2
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	10,922	10,794
Corporate bonds | Level 3
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 securities
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	6	15
Mortgage-backed securities | Level 1
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 securities | Level 2
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	6	15
Mortgage-backed securities | Level 3
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
Municipal bonds
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	267	0
Municipal bonds | Level 1
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	267	0
Municipal bonds | Level 2
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
Municipal bonds | Level 3
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
Mutual Funds
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	20,130	26,791
Mutual Funds | Level 1
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	20,130	26,791
Mutual Funds | Level 2
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
Mutual Funds | Level 3
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
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	16	33
Preferred stock | Level 1
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 | Level 2
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	16	33
Preferred stock | Level 3
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