Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Condensed Consolidated Balance Sheets [Abstract]
Allowances for patient receivables, current	$ 1,002	$ 1,035
Allowances for patient receivables, non-current	$ 719	$ 634
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares issued	25,291,637	25,291,637
Common stock, shares outstanding	18,972,134	18,858,147
Treasury stock, shares	6,319,503	6,433,490