Accounts receivables, net and other receivables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts receivables, net and other receivables
Trade receivables, net of allowances	$ 41,736	$ 25,562
Unbilled access fees	1,654	2,142
Unbilled platform service arrangements	162	213
Accounts Receivable, Net, Current, Total	43,552	27,917
Unbilled access fees	360	115
Unbilled platform service arrangements	3,472	0
Non-current other receivables	3,832	115
Allowance for doubtful accounts
Balance at the beginning of the period	394	345	$ 179
Additions charged to operations	304	191	209
Deductions from reserves, net	(93)	(142)	(43)
Balance at the end of the period	$ 605	$ 394	$ 345