Net Loss Per Share - Additional Information (Detail)	3 Months Ended		6 Months Ended		1 Months Ended	12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 20, 2012 Elan [Member]	Dec. 31, 2012 Elan [Member]
Earnings Per Share [Line Items]
Share issue due to separation	17,679,000	14,497,000	17,679,000	14,497,000		14,497,000
Shares issued for cash consideration					3,182,000