Annual report pursuant to Section 13 and 15(d)

Common Stock, Stock-Based Awards and Warrants - Stock Options Narrative (Details)

v3.19.1
Common Stock, Stock-Based Awards and Warrants - Stock Options Narrative (Details) - USD ($)
1 Months Ended 12 Months Ended
Jul. 27, 2017
Jul. 27, 2016
Mar. 31, 2017
Aug. 31, 2016
Dec. 31, 2013
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Aug. 31, 2018
Jun. 25, 2018
Jan. 18, 2018
Dec. 21, 2017
Mar. 31, 2016
Class of Stock [Line Items]                          
Number of shares authorized for repurchase                         $ 50,000,000.0
Remaining shares amount authorized repurchase amount           $ 44,800,000              
2013 Equity Incentive Plan                          
Class of Stock [Line Items]                          
Number of grants available (in shares)               11,000,000          
Remaining stock-based awards available (in shares)                     7,070,298    
2017 Equity Incentive Plan                          
Class of Stock [Line Items]                          
Number of grants available (in shares)                   2,000,000   6,500,000  
Stock Options | 2013 Equity Incentive Plan                          
Class of Stock [Line Items]                          
Remaining stock-based awards available (in shares)                       2,097,846  
Vesting period           4 years              
Options exercised, intrinsic value           $ 0 $ 0 $ 0          
Stock Options | 2013 Equity Incentive Plan | First Anniversary                          
Class of Stock [Line Items]                          
Percent of stock options vesting on the anniversary of commencement (as a percent)         25.00%                
Stock Options | 2013 Equity Incentive Plan | After First Anniversary                          
Class of Stock [Line Items]                          
Vesting period           3 years              
Percent of stock options vesting on the anniversary of commencement (as a percent)         2.083%                
Restricted stock units                          
Class of Stock [Line Items]                          
Non-options granted (in shares)           3,392,000              
Stock option term (in years)           4 years              
Percent of stock options vesting on the anniversary of commencement (as a percent)           25.00%              
Restricted stock units | Board of Directors                          
Class of Stock [Line Items]                          
Non-options granted (in shares)           0 268,000            
Vesting period           12 months 12 months            
Common Stock                          
Class of Stock [Line Items]                          
Issuance of common stock for Emerging Markets Communication Acquisition (in shares)               5,467,000          
Issuance of common stock for legal settlements (in shares)               1,751,000          
Common Stock | UMG Recordings | Price Per Share Scenario One                          
Class of Stock [Line Items]                          
Shares issued in period (in shares)     500,000 500,000                  
Share price (in usd per share)     $ 10.00     $ 10.00     $ 10.00        
Common Stock | UMG Recordings | Price Per Share Scenario Two                          
Class of Stock [Line Items]                          
Shares issued in period (in shares)     400,000 400,000                  
Share price (in usd per share)     $ 12.00     $ 12.00     $ 12.00        
Emerging Markets Communications LLC                          
Class of Stock [Line Items]                          
Business combination, additional consideration payable, percent payable at fixed rate   50.00%                      
Business combination, additional consideration payable, portion payable at fixed rate, price per share   $ 8.40                      
Business combination, additional consideration payable, percent payable at variable rate   50.00%                      
Business combination, additional consideration payable, portion at variable rate, measurement period prior to anniversary date   2 days                      
Emerging Markets Communications LLC | President | 2016 Inducement And Retention Stock Plan For EMC Employees | Share-based Compensation Award, Tranche Two                          
Class of Stock [Line Items]                          
Vesting period   2 years                      
Emerging Markets Communications LLC | EMC Employees | 2016 Inducement And Retention Stock Plan For EMC Employees | Share-based Compensation Award, Tranche Two                          
Class of Stock [Line Items]                          
Vesting period   3 years                      
Emerging Markets Communications LLC | Stock Options | President | 2016 Inducement And Retention Stock Plan For EMC Employees                          
Class of Stock [Line Items]                          
Options granted (in shares)   450,000                      
Emerging Markets Communications LLC | Stock Options | EMC Employees | 2016 Inducement And Retention Stock Plan For EMC Employees                          
Class of Stock [Line Items]                          
Options granted (in shares)   72,600                      
Emerging Markets Communications LLC | Restricted stock units | President | 2016 Inducement And Retention Stock Plan For EMC Employees                          
Class of Stock [Line Items]                          
Non-options granted (in shares)   275,000                      
Emerging Markets Communications LLC | Restricted stock units | EMC Employees | 2016 Inducement And Retention Stock Plan For EMC Employees                          
Class of Stock [Line Items]                          
Non-options granted (in shares)   73,750                      
Emerging Markets Communications LLC | Restricted Stock | President | 2016 Inducement And Retention Stock Plan For EMC Employees                          
Class of Stock [Line Items]                          
Non-options granted (in shares)   175,000                      
Emerging Markets Communications LLC | Common Stock                          
Class of Stock [Line Items]                          
Issuance of common stock for Emerging Markets Communication Acquisition (in shares) 5,000,000 5,500,000                      
Minimum | Stock Options | 2013 Equity Incentive Plan                          
Class of Stock [Line Items]                          
Stock option term (in years)           5 years              
Minimum | Stock Options | Board of Directors | 2013 Equity Incentive Plan                          
Class of Stock [Line Items]                          
Stock option term (in years)           5 years              
Maximum | Stock Options | 2013 Equity Incentive Plan                          
Class of Stock [Line Items]                          
Stock option term (in years)           7 years              
Maximum | Stock Options | Board of Directors | 2013 Equity Incentive Plan                          
Class of Stock [Line Items]                          
Stock option term (in years)           7 years              
Settled Litigation | UMG Recordings                          
Class of Stock [Line Items]                          
Issuance of common stock for legal settlements (in shares)       1,800,000