Commitments and Contingencies (Tables) - Customer Concentration Risk

6 Months Ended

Jun. 30, 2016

Sales

Schedule of Significant Customers, Revenue and Accounts Receivable Concentration Information

The following table reflects the percentage of total revenue from such customer for the three and six months ended June 30, 2015 and 2016:

	Three months ended June 30,						Six months ended June 30,
	2015			2016			2015			2016
Subsidiaries of AT&T		77.7	%		87.9	%		76.2	%		86.6	%
Other		22.3	%		12.1	%		23.8	%		13.4	%

Accounts Receivable

Schedule of Significant Customers, Revenue and Accounts Receivable Concentration Information

Amounts due from these significant customers at December 31, 2015 and June 30, 2016 were as follows (in thousands):

	December 31, 2015		June 30, 2016
Subsidiaries of AT&T	$	9,787	$	2,583