Summary of Cash, Cash Equivalents, Short-Term investments, and Restricted Cash and Investments (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Cash and cash equivalents:
Cash	$ 35,269	$ 50,550
Cash equivalents		6,551
Cash and cash equivalents	35,269	57,101	43,656	36,940
Short-term investments		17,916
Restricted cash and investments:
Restricted cash and investments	10,401	2,138
Restricted cash and investments, non-current	12,250
Total restricted cash and investments	$ 22,651	$ 2,138