Net Loss Per Ordinary Share - Ordinary Shares Equivalent Not Included in Diluted Net Loss Per Share (Detail) (Options to purchase ordinary shares [Member]) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Options to purchase ordinary shares [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Equivalent ordinary shares not included in diluted net loss per share	2,612	1,974	1,005