Summary of Significant Accounting Policies, Part 2 (Details) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Cash, Cash Equivalents and Marketable Securities [Abstract]
Impairment losses for other-than-temporary decline in fair value	$ 0	$ 0	$ 0
Money market funds and debt securities	2,200,000	3,300,000
Cash and cash equivalents held in foreign bank accounts	639,000	858,000
Amortized cost and fair value of marketable securities classified as available-for-sale [Abstract]
Held-to-maturity certificates of deposit	4,180,000	8,600,000
Inventories [Abstract]
Raw materials	219,000	219,000
Work-in-process	21,000	1,000
Finished goods	479,000	479,000
Inventories	718,933	698,742
US Government and Agency debt securities [Member]
Amortized cost and fair value of marketable securities classified as available-for-sale [Abstract]
Amortized Cost	7,209,000	3,031,000
Unrealized Gains	1,000	0
Unrealized Losses	(1,000)	(1,000)
Fair Value	7,209,000	3,030,000
Short-term Investments [Member]
Amortized cost and fair value of marketable securities classified as available-for-sale [Abstract]
Held-to-maturity certificates of deposit	4,200,000	6,200,000
Short-term Investments [Member] | US Government and Agency debt securities [Member]
Amortized cost and fair value of marketable securities classified as available-for-sale [Abstract]
Amortized Cost	3,756,000	1,001,000
Unrealized Gains	1,000	0
Unrealized Losses	0	0
Fair Value	3,757,000	1,001,000
Long-term Investments [Member]
Amortized cost and fair value of marketable securities classified as available-for-sale [Abstract]
Held-to-maturity certificates of deposit	0	2,400,000
Long-term Investments [Member] | US Government and Agency debt securities [Member]
Amortized cost and fair value of marketable securities classified as available-for-sale [Abstract]
Amortized Cost	3,453,000	2,030,000
Unrealized Gains	0	0
Unrealized Losses	(1,000)	(1,000)
Fair Value	3,452,000	2,029,000
Maturity period of available-for-sale securities	2 years
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | US Government and Agency debt securities [Member]
Assets carried at fair value measured on a recurring basis [Abstract]
U.S. Government and Agency debt securities	3,757,000	1,001,000
Fair Value, Measurements, Recurring [Member] | Long-term Investments [Member] | US Government and Agency debt securities [Member]
Assets carried at fair value measured on a recurring basis [Abstract]
U.S. Government and Agency debt securities	3,452,000	2,029,000
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member] | US Government and Agency debt securities [Member]
Assets carried at fair value measured on a recurring basis [Abstract]
U.S. Government and Agency debt securities	0	0
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member] | US Government and Agency debt securities [Member]
Assets carried at fair value measured on a recurring basis [Abstract]
U.S. Government and Agency debt securities	0	0
Fair Value, Measurements, Recurring [Member] | Significant Observable Inputs (Level 2) [Member] | Short-term Investments [Member] | US Government and Agency debt securities [Member]
Assets carried at fair value measured on a recurring basis [Abstract]
U.S. Government and Agency debt securities	3,757,000	1,001,000
Fair Value, Measurements, Recurring [Member] | Significant Observable Inputs (Level 2) [Member] | Long-term Investments [Member] | US Government and Agency debt securities [Member]
Assets carried at fair value measured on a recurring basis [Abstract]
U.S. Government and Agency debt securities	3,452,000	2,029,000
Maximum period for maturity of debt securities	2 years
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member] | US Government and Agency debt securities [Member]
Assets carried at fair value measured on a recurring basis [Abstract]
U.S. Government and Agency debt securities	0	0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member] | US Government and Agency debt securities [Member]
Assets carried at fair value measured on a recurring basis [Abstract]
U.S. Government and Agency debt securities	$ 0	$ 0