Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accounting Policies [Abstract]
Impairment loss			$ 0
Oncology practice combined represented revenue	16.50%	12.90%	15.80%	15.40%
Revenue of all other clients individually			Less than 5%
Largest amount of tax benefit			Greater than 50%
Income tax expense	$ 29,000		$ 46,000