Commitments and Contingencies - Additional Information (Detail) $ / shares in Units, £ in Thousands		12 Months Ended	96 Months Ended
	Oct. 26, 2015 shares	Dec. 31, 2008 GBP (£)	Dec. 31, 2015 GBP (£)	Dec. 31, 2015 USD ($) Contracts $ / £	Mar. 31, 2015 USD ($)	Apr. 30, 2014 $ / shares shares
Commitments And Contingencies Disclosure [Abstract]
Research and development grant funding from Scottish Enterprise | £		£ 1,791
Claims from grant | £			£ 1,790
Number of forward exchange contracts | Contracts				12
Forward exchange contracts sold | $				$ 500,000
Forward exchange contract US Dollars to pound sterling | $ / £				1.50
Issued warrants to acquire common shares						5,000,000
Ordinary share acquired for each unit of warrant						0.8
Exercise of warrants per share | $ / shares						$ 8.80
Number of warrants exercised	4,981,052
Number of warrants expired	18,948
Financial liability of outstanding warrants | $				$ 0	$ 31,011,000