Other Assets - Additional Information (Detail) (Chemo Centryx, Inc., USD $) In Millions, unless otherwise specified	1 Months Ended
	Sep. 30, 2011
Chemo Centryx, Inc.
Related Party Transaction [Line Items]
Notes Receivable	$ 10
Notes Receivable Interest Rate	5.00%
Notes Receivable, Maturity Date	Sep. 30, 2021
Commitment to participate in private placement of CCX shares	$ 5