Investments - Summary by Type of Instruments Measured at Fair Value (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cash, cash equivalents and available-for-sale investments measured at fair value on recurring basis	$ 75,358		$ 106,583
Level 1
Schedule of Available-for-sale Securities [Line Items]
Cash, cash equivalents and available-for-sale investments measured at fair value on recurring basis	64,516		90,740
Level 2
Schedule of Available-for-sale Securities [Line Items]
Cash, cash equivalents and available-for-sale investments measured at fair value on recurring basis	10,842		15,843
Level 3
Schedule of Available-for-sale Securities [Line Items]
Cash, cash equivalents and available-for-sale investments measured at fair value on recurring basis	0		0
Cash
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents measured at fair value on a recurring basis	33,936		65,867
Cash | Level 1
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents measured at fair value on a recurring basis	33,936		65,867
Cash | Level 2
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents measured at fair value on a recurring basis	0		0
Cash | Level 3
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents measured at fair value on a recurring basis	0		0
Cash Equivalents
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents measured at fair value on a recurring basis	2,559		5,672
Cash Equivalents | Level 1
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents measured at fair value on a recurring basis	2,559		5,672
Cash Equivalents | Level 2
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents measured at fair value on a recurring basis	0		0
Cash Equivalents | Level 3
Schedule of Available-for-sale Securities [Line Items]
Cash and cash equivalents measured at fair value on a recurring basis	0		0
U.S Treasury Securities and Agency Bonds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	1,230		2,838
U.S Treasury Securities and Agency Bonds | Level 1
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	1,230		2,838
U.S Treasury Securities and Agency Bonds | Level 2
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	0		0
U.S Treasury Securities and Agency Bonds | Level 3
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	0		0
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	10,794		10,627
Corporate bonds | Level 1
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	0		0
Corporate bonds | Level 2
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	10,794		10,627
Corporate bonds | Level 3
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	0		0
Mortgage Backed and Asset Backed Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	15	[1]	2,074	[1]
Mortgage Backed and Asset Backed Securities | Level 1
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	0		0
Mortgage Backed and Asset Backed Securities | Level 2
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	15		2,074
Mortgage Backed and Asset Backed Securities | Level 3
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	0		0
Mutual funds
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	26,791		16,363
Mutual funds | Level 1
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	26,791		16,363
Mutual funds | Level 2
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	0		0
Mutual funds | Level 3
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	0		0
Preferred Stock
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	33		3,142
Preferred Stock | Level 1
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	0		0
Preferred Stock | Level 2
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	33		3,142
Preferred Stock | Level 3
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	$ 0		$ 0

[1] At March 31, 2015 and 2014, zero and $1.1 million of the estimated fair value presented were mortgage-backed securities, respectively.