Equity Method Investment - Additional Information (Detail) £ in Thousands, $ in Thousands	1 Months Ended							12 Months Ended
	Nov. 30, 2015 USD ($) shares	Nov. 30, 2015 GBP (£) shares	Oct. 31, 2014 USD ($) shares	Jul. 31, 2014 USD ($) shares	Jul. 31, 2014 GBP (£) shares	Feb. 28, 2014 USD ($) shares	Feb. 28, 2014 GBP (£) shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Equity Method Investments [Line Items]
Amount raised by equity investee on shares issued								$ 317	$ 1,666	$ 1,610
Gain (Loss) on dilution of equity method investment								$ (7)	$ 954
Warrants exercised amount			$ 500
Warrants exercised shares | shares			6,155,000
Equity investment ownership position								15.11%
Carrying value of equity investment								$ 2,536
Quoted market value of equity investment								$ 1,850
TyraTech Inc.
Equity Method Investments [Line Items]
Shares issued by equity investee | shares	105,333,333	105,333,333		50,000,000	50,000,000	37,391,763	37,391,763
Amount raised by equity investee on shares issued	$ 4,800	£ 3,200		$ 5,900	£ 3,500	$ 3,100	£ 1,870