Quarterly report pursuant to Section 13 or 15(d)

Common Stock, Share-based Awards and Warrants - Narrative (Details)

v3.10.0.1
Common Stock, Share-based Awards and Warrants - Narrative (Details) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended 9 Months Ended
Jun. 25, 2018
Jul. 27, 2017
Jul. 27, 2016
Mar. 31, 2017
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Jan. 30, 2018
Dec. 31, 2017
Dec. 21, 2017
Dec. 31, 2016
Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Stock repurchase program, authorized amount                         $ 50,000
Stock repurchase program, remaining authorized amount         $ 44,800   $ 44,800            
Aggregate estimated fair value of phantom stock options         1,240   1,240            
Income recorded as a result of remeasurement         $ (196) $ 196 $ (287) $ 2,672          
Equity Incentive Plan, 2013                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Number of shares authorized (in shares)                       11,000,000  
Equity Incentive Plan, 2013 | Employee Stock Options                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Shares available for grant                     2,337,466    
Equity Incentive Plan, 2017                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Number of shares authorized (in shares)                     6,500,000    
Additional shares authorized 2,000,000                        
Public SPAC Warrants                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Warrants outstanding         0   0     6,173,000      
Common Stock | Emerging Markets Communications LLC                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Stock issued during period, acquisitions (in shares)   5,000,000 5,500,000                    
Price per share of stock issued during period, acquisitions   $ 8.40                      
Quotes prices in active markets (Level 1)                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Aggregate estimated fair value of phantom stock options         $ 0   $ 0            
Public Warrants | Quotes prices in active markets (Level 1) | Public SPAC Warrants                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Number of warrants (in shares)                 6,173,228        
Price Per Share Scenario Two | Common Stock | UMG Recordings                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Stock issued during period, litigation (in shares)       400,000                  
Share price of common stock (in usd per share)           $ 12.00   $ 12.00          
Price Per Share Scenario One | Common Stock | UMG Recordings                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Stock issued during period, litigation (in shares)       500,000                  
Share price of common stock (in usd per share)           $ 10.00   $ 10.00          
Public SPAC Warrants                          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                          
Change in value           $ 100 $ 100 $ (300)