Business and Liquidity (Details) (USD $)	0 Months Ended	3 Months Ended
	Feb. 22, 2013	Mar. 31, 2013 item	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2011
Business and Liquidity
Period since the entity has begun commercialization outside the United States of its newest product, RenalGuard		5 years
Number of operating segments		1
Loss from operations		$ 7,808,000
Cash used in operations		2,158,000	949,000
Cash and cash equivalents		1,863,000	1,601,000	258,000	2,585,000
Additional capital	$ 4,040,000
Number of independent investigator-sponsored clinical trials		2