Significant Risk Concentrations - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended			9 Months Ended			12 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Korea [Member]	Sep. 30, 2012 Windows Mobile Operating Systems [Member] Korea [Member]	Sep. 30, 2012 Windows Mobile Operating Systems [Member] Korea [Member]	Sep. 30, 2013 Cost of revenue - service [Member]	Sep. 30, 2012 Cost of revenue - service [Member]	Sep. 30, 2013 Cost of revenue - service [Member]	Sep. 30, 2012 Cost of revenue - service [Member]	Sep. 30, 2013 Reduction in marketing expense in the future [Member]	Sep. 30, 2013 Other customer [Member] Revenue [Member] Customer	Sep. 30, 2012 Other customer [Member] Revenue [Member] Customer	Sep. 30, 2013 Other customer [Member] Revenue [Member] Customer	Sep. 30, 2012 Other customer [Member] Revenue [Member] Customer	Sep. 30, 2013 Other customer [Member] Accounts receivable [Member] Customer	Dec. 31, 2012 Other customer [Member] Accounts receivable [Member] Customer	Sep. 30, 2013 Bluebird Soft, Inc.[Member]	Dec. 31, 2012 Bluebird Soft, Inc.[Member]	Dec. 31, 2012 Bluebird Soft, Inc.[Member] Accounts receivable [Member]
Concentration Risk [Line Items]
Number of other customer account as major customer														0	0	0	0	0	0
Accounts receivable	$ 12,811,000		$ 12,811,000		$ 16,095,000																$ 2,100,000
Concentration risk, percentage																						13.00%
Accounts receivable collected																				2,100,000
Expiration date one of OEM Distribution agreements for embedded operating systems			Sep. 30, 2014
Expiration date of OEM Distribution agreements for mobile operating systems, non-EMEA			Sep. 30, 2014
Rights expired for Windows Mobile operating systems in Korea						Oct. 31, 2012
Revenue	18,456,000	19,635,000	51,818,000	55,645,000			1,200,000	2,900,000
Earnings under the rebate program									$ 89,000	$ 196,000	$ 658,000	$ 609,000	$ 208,000