Revenue by Geographical Location (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue, Major Customer [Line Items]
Revenue	$ 9,656	$ 8,045	$ 8,830	$ 7,692	$ 9,587	$ 10,362	$ 8,601	$ 7,866	$ 34,223	$ 36,416	$ 39,657
FRANCE
Revenue, Major Customer [Line Items]
Revenue									7,732	9,184	7,030
SPAIN
Revenue, Major Customer [Line Items]
Revenue									4,070	2,776	7,033
CIS
Revenue, Major Customer [Line Items]
Revenue									3,361	6,636	8,220
BELGIUM
Revenue, Major Customer [Line Items]
Revenue									5,728	4,456	3,971
SWITZERLAND
Revenue, Major Customer [Line Items]
Revenue									2,938	3,784	4,078
Other Countries
Revenue, Major Customer [Line Items]
Revenue									$ 10,394	$ 9,580	$ 9,325