Income Taxes - NOLs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net operating loss carry-forwards
Interest expense recognized for uncertain tax positions	$ 0	$ 0	$ 0
Penalties recognized for uncertain tax positions	0	$ 0	$ 0
U.S. federal
Net operating loss carry-forwards
Net operating loss carry-forwards	117,308
U.S. federal | Transpera, Inc.
Net operating loss carry-forwards
Net operating loss carry-forwards available to offset future taxable income annually under Section 382	160
U.S. federal | ScanScout
Net operating loss carry-forwards
Net operating loss carry-forwards available to offset future taxable income annually under Section 382	2,220
State
Net operating loss carry-forwards
Net operating loss carry-forwards	65,659
Foreign | United Kingdom
Net operating loss carry-forwards
Net operating loss carry-forwards	8,153
Foreign | Germany
Net operating loss carry-forwards
Net operating loss carry-forwards	6,787
Foreign | Brazil
Net operating loss carry-forwards
Net operating loss carry-forwards	99
U.S. federal and state
Net operating loss carry-forwards
Net operating losses from excess tax deductions attributable to equity compensation	$ 3,885