Stock incentive plans (Tables)

12 Months Ended

Dec. 31, 2015

Stock incentive plans

Schedule of stock-based compensation expense

	Years ended December 31,
	2015		2014		2013
Network operations	$	1,504	$	1,356	$	888
Development and technology		731		600		380
Selling and marketing		3,411		2,017		1,045
General and administrative		3,752		3,191		2,193
Total stock-based compensation expense	$	9,398	$	7,164	$	4,506

Summary of stock option activity

	Number of Options (000's)			Weighted Average Exercise Price		Weighted- Average Remaining Contract Life (years)		Aggregate Intrinsic Value
Outstanding at December 31, 2014		4,341		$	6.60		5.8	$	11,017
Exercised		(440	)	$	3.12
Canceled/forfeited		(153	)	$	9.51
Outstanding at December 31, 2015		3,748		$	6.89		5.0	$	6,611
Vested, exercisable and expected to vest at December 31, 2015		3,728		$	6.89		5.0	$	6,605
Exercisable at December 31, 2015		3,175		$	6.73		4.6	$	6,475

Summary of nonvested RSU activity under the 2011 Plan

	Number of Shares (000's)			Weighted Average Grant Date Fair Value
Non-vested at December 31, 2014		1,385		$	6.09
Granted		1,472		$	7.55
Vested		(949	)	$	7.69
Canceled/forfeited		(89	)	$	7.14
Non-vested at December 31, 2015		1,819		$	6.39