Segments and Geographic Information - Selected Information by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 13,956	$ 11,610	$ 25,203	$ 22,087
Total assets	60,028		60,028		$ 57,571
Total Long-lived assets	15,847		15,847		14,502
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	2,387	2,421	4,015	4,215
Total assets	21,494		21,494		21,423
Total Long-lived assets	667		667		663
Switzerland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	9,759	7,350	17,516	13,691
Total assets	33,566		33,566		4,673
Total Long-lived assets	460		460		369
Nottingham, UK Facility [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	1,088	1,142	2,037	2,493
Total assets	4,838		4,838		31,288
Total Long-lived assets	14,718		14,718		13,468
Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	722	$ 697	1,635	$ 1,688
Total assets	130		130		187
Total Long-lived assets	$ 2		$ 2		$ 2