Activity of Awarded Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Shares Under Options
Outstanding at beginning of year (in shares)	2,286,734
Granted (in shares)	934,067
Exercised (in shares)	(2,820)	0
Forfeited (in shares)	(88,912)
Outstanding at end of year (in shares)	3,129,069	2,286,734
Exercisable at end of year (in shares)	2,167,686
Weighted- Average Exercise Price
Outstanding at beginning of year (in dollars per share)	$ 21.14
Granted (in dollars per share)	$ 4.32
Exercised (in dollars per share)	$ 5.67
Forfeited (in dollars per share)	$ 20.50
Outstanding at end of year (in dollars per share)	$ 16.15	$ 21.14
Exercisable at end of year (in dollars per share)	$ 20.39
Weighted- Average Remaining Contractual Term
Outstanding at end of year	6 years 8 months 12 days
Exercisable at end of year	5 years 9 months 18 days
Aggregate Intrinsic Value
Outstanding at end of year	$ 1,413
Exercisable at end of year	$ 443