WARRANTY RESERVES (Details) (USD $)	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2012
Change in accrued warranty reserve [Roll Forward]
Balance at beginning of period	$ 1,494,000	$ 1,470,000	$ 1,846,000	$ 1,222,000
Provision for warranty expense	354,000	270,000	661,000	613,000
Warranty costs incurred	(368,000)	(304,000)	(737,000)	(656,000)
Adjustment to pre-existing warranties	0	0	(290,000)	257,000
Balance at end of period	1,480,000	1,436,000	1,480,000	1,436,000
Non-current portion of warranty reserve	437,000	313,000	437,000	313,000
Current portion of warranty reserve	1,043,000	1,123,000	1,043,000	1,123,000
Warranty reserve [Abstract]
Current portion of warranty reserve	1,043,000		1,043,000		1,245,000
Instruments [Member]
Product Warranty Liability [Line Items]
Period of coverage for standard warranty obligation on instruments (in years)			one to three years
Reagent Discs [Member]
Warranty reserve [Abstract]
Warranty reserve, balance at end of period	623,000		623,000		564,000
Current portion of warranty reserve	$ 623,000		$ 623,000		$ 564,000