Description of the Company's Business and Basis of Presentation - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2013
Maximum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Health care contracts initial term	2 years
Health care contracts cancellation written notice period	90 days
Minimum [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Health care contracts initial term	1 year
Health care contracts cancellation written notice period	60 days