Accounts receivables, net and other receivables (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts receivables, net and other receivables
Trade receivables, net of allowances	$ 12,799	$ 10,977
Unbilled access fees	2,036	1,957
Unbilled platform service arrangements	1,491	109
Accounts receivable, net	16,326	13,043
Unbilled access fees	264	838
Unbilled platform service arrangements	16	287
Non-current other receivables	280	1,125
Allowance for doubtful accounts
Balance at the beginning of the period	179	177	107
Additions charged to operations	209	45	115
Deductions from reserves, net	(43)	(43)	(45)
Balance at the end of the period	$ 345	$ 179	$ 177