Cash Equivalents and Marketable Securities (Details) (USD $)	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Mar. 31, 2012
Cash Equivalents and Marketable Securities [Abstract]
Impairment losses for other-than-temporary decline in fair value	$ 0	$ 0
Money market funds	2,700,000		3,300,000
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,241,000		3,031,000
Unrealized Gains	0		0
Unrealized Losses	2,000		1,000
Fair Value	6,239,000		3,030,000
Short-term Investments [Member] | US Government and Agency debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,019,000		1,001,000
Unrealized Gains	0		0
Unrealized Losses	1,000		0
Fair Value	3,018,000		1,001,000
Short-term Investments [Member] | Bank holding company debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,216,000
Unrealized Gains	0
Unrealized Losses	1,000
Fair Value	2,215,000
Long-term Investments [Member] | US Government and Agency debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,006,000		2,030,000
Unrealized Gains	0		0
Unrealized Losses	0		1,000
Fair Value	1,006,000		2,029,000
Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Maturity period of available-for-sale securities	2 years
Certificates of Deposit [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-maturity securities	$ 5,300,000		$ 8,600,000
Certificates of Deposit [Member] | Minimum [Member]
Schedule of Held-to-maturity Securities [Line Items]
Maturity period of held-to-maturity securities	1 month
Certificates of Deposit [Member] | Maximum [Member]
Schedule of Held-to-maturity Securities [Line Items]
Maturity period of held-to-maturity securities	15 months