Condensed Financial Information of Registrant (Parent Only) Balance Sheets (Parenthetical) (Detail)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2014 Parent Company USD ($)	Dec. 31, 2014 Parent Company EUR (€)	Dec. 31, 2013 Parent Company USD ($)	Dec. 31, 2013 Parent Company EUR (€)	Dec. 31, 2014 Ordinary Shares A	Dec. 31, 2013 Ordinary Shares A	Dec. 31, 2014 Ordinary Shares A Parent Company	Dec. 31, 2013 Ordinary Shares A Parent Company	Dec. 31, 2014 Ordinary Shares B	Dec. 31, 2013 Ordinary Shares B	Dec. 31, 2014 Ordinary Shares B Parent Company	Dec. 31, 2013 Ordinary Shares B Parent Company
Condensed Financial Statements, Captions [Line Items]
Ordinary shares, par value	$ 0.0001	$ 0.0001	$ 0.0001		$ 0.0001
Ordinary shares, shares authorized	900,000,000	900,000,000	900,000,000	900,000,000	900,000,000	900,000,000
Ordinary shares, shares issued							16,331,577	16,200,406	16,331,577	16,200,406	12,061,370	12,061,370	12,061,370	12,061,370
Ordinary shares, shares outstanding							13,266,762	13,141,035	13,266,762	13,141,035	12,061,370	12,061,370	12,061,370	12,061,370
Deferred shares, par value				€ 1		€ 1
Deferred shares, shares authorized			40,000	40,000	40,000	40,000
Deferred shares, shares issued			40,000	40,000	40,000	40,000
Deferred shares, shares outstanding			40,000	40,000	40,000	40,000
Preferred shares, par value			$ 0.0001		$ 0.0001
Preferred shares, shares authorized			100,000,000	100,000,000	100,000,000	100,000,000
Preferred shares, shares issued			0	0	0	0
Preferred shares, shares outstanding			0	0	0	0
Treasury shares, cost							3,064,815	3,059,371	3,064,815	3,059,371