Segment reporting and concentrations (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jul. 28, 2014
Segment Reporting Information [Line Items]
Revenues		$ 15,674	$ 16,060	$ 15,642	$ 15,698	$ 15,523	$ 15,135	$ 14,063	$ 13,802	$ 63,074	$ 58,523	$ 59,076
Income (loss) before provision for income taxes										(4,785)	(2,181)	(1,520)
Assets		47,588				51,237				47,588	51,237
Goodwill		2,734				1,476				2,734	1,476	1,635	$ 1,034
Before Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Income (loss) before provision for income taxes	[1]									(4,785)	(2,181)	(1,520)
After Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Income (loss) before provision for income taxes	[2]									(4,785)	(2,181)	(1,520)
IADS [Member]
Segment Reporting Information [Line Items]
Revenues										4,347	2,111	614
Assets		1,282				1,026				1,282	1,026
IADS [Member] | Before Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Income (loss) before provision for income taxes	[1]									(4,664)	(6,176)	(7,572)
IADS [Member] | After Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Income (loss) before provision for income taxes	[2]									(1,778)	(3,685)	(5,582)
MIS [Member]
Segment Reporting Information [Line Items]
Income (loss) before provision for income taxes										8,088	4,691	1,668
Assets		21,874				8,369				21,874	8,369
Goodwill		2,059				801				2,059	801
MIS [Member] | Before Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Income (loss) before provision for income taxes	[1]									(1,258)	(1,230)	(304)
MIS [Member] | After Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Income (loss) before provision for income taxes	[2]									(1,231)	(1,208)	(301)
DDS [Member]
Segment Reporting Information [Line Items]
Revenues										50,639	51,721	56,794
Assets		24,432				41,842				24,432	41,842
Goodwill		$ 675				$ 675				675	675
DDS [Member] | Before Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Income (loss) before provision for income taxes	[1]									1,137	5,225	6,356
DDS [Member] | After Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Income (loss) before provision for income taxes	[2]									$ (1,776)	$ 2,712	$ 4,363

[1] Before elimination of any inter-segment profits

[2] After elimination of any inter-segment profits