Overview and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Initial offering period			December 2011
Online game revenue and income from operations	$ 500,000		$ 900,000
Discontinued game revenue from adjustments of prior period deferred revenue		$ 0		$ 0
Impact on reported earnings per share	$ 0		$ 0.01
Changes in revenue from adjustments of prior period deferred revenue	$ 0	$ 0	$ 0	$ 0
Minimum [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Stipulate payment terms as specific number of days subsequent to end of the month			30 days
Maximum [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Stipulate payment terms as specific number of days subsequent to end of the month			60 days
Facebook [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Percentage of transaction fee recognized price			70.00%
Consumable Virtual Items [Member]
Revenue Recognition Multiple Deliverable Arrangements [Line Items]
Revenue recognition period			1 month