Stockholders' Equity (Tables)
   | 
9 Months Ended | 
Sep. 30, 2021  | 
| Stockholders' Equity | 
 
 | 
| Schedule of Stock-Based Compensation Expense | 
 The following table summarizes the stock-based compensation expense from stock option, employee stock purchase programs and restricted Common Stock awards and warrants for the three months ended September 30, 2021 and 2020: 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
  | 
  | 
Three Months Ended September 30,   | 
  | 
Nine Months Ended September 30,   | 
  | 
 
($ in thousands)  | 
      | 
2021  | 
      | 
2020  | 
      | 
2021  | 
      | 
2020  | 
  | 
 
Employee and non-employee awards  | 
  | 
$  | 
 2,185  | 
  | 
$  | 
 1,231  | 
  | 
$  | 
 6,236  | 
  | 
$  | 
 3,868  | 
  | 
 
Executive awards of Fortress Companies' stock  | 
  | 
   | 
 377  | 
  | 
   | 
 369  | 
  | 
   | 
 1,070  | 
  | 
   | 
 1,136  | 
  | 
 
Warrants  | 
  | 
  | 
 —  | 
  | 
  | 
 32  | 
  | 
  | 
 —  | 
  | 
  | 
 97  | 
  | 
 
Partner  Companies:  | 
  | 
   | 
  | 
  | 
  | 
  | 
  | 
   | 
  | 
  | 
  | 
  | 
  | 
 
Avenue  | 
  | 
   | 
 69  | 
  | 
   | 
 161  | 
  | 
   | 
 299  | 
  | 
   | 
 592  | 
  | 
 
Checkpoint  | 
  | 
   | 
 779  | 
  | 
   | 
 725  | 
  | 
   | 
 2,319  | 
  | 
   | 
 2,095  | 
  | 
 
Mustang  | 
  | 
   | 
 884  | 
  | 
   | 
 606  | 
  | 
   | 
 2,427  | 
  | 
   | 
 2,368  | 
  | 
 
Other  | 
  | 
   | 
 32  | 
  | 
   | 
 47  | 
  | 
   | 
 98  | 
  | 
   | 
 163  | 
  | 
 
Total stock-based compensation expense  | 
  | 
$  | 
 4,326  | 
  | 
$  | 
 3,171  | 
  | 
$  | 
 12,449  | 
  | 
$  | 
 10,319  | 
  | 
 
 
 
 | 
| Schedule of Stock Option Activities | 
 The following table summarizes Fortress stock option activities excluding activity related to Fortress partner companies: 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
Weighted average  | 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
Total  | 
  | 
remaining  | 
 
  | 
  | 
  | 
  | 
Weighted average  | 
  | 
weighted average  | 
  | 
contractual life  | 
 
  | 
      | 
Number of shares  | 
      | 
exercise price  | 
      | 
intrinsic value  | 
      | 
(years)  | 
 
Options vested and expected to vest at December 31, 2020  | 
   | 
 1,053,490  | 
  | 
$  | 
 5.02  | 
  | 
$  | 
 647,482  | 
   | 
 2.63  | 
 
Forfeited  | 
  | 
 (35,000)  | 
  | 
  | 
 4.33  | 
  | 
  | 
 —  | 
  | 
 —  | 
 
Options vested and expected to vest at September 30, 2021  | 
   | 
 1,018,490  | 
  | 
$  | 
 5.04  | 
  | 
$  | 
 666,957  | 
   | 
 1.93  | 
 
Options vested and exercisable at September 30, 2021  | 
  | 
 1,018,490  | 
  | 
$  | 
 5.04  | 
  | 
$  | 
 666,957  | 
   | 
 1.93  | 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
 
 
 
 | 
| Schedule of Restricted Stock Awards and Restricted Stock Units | 
 The following table summarizes Fortress restricted stock awards and restricted stock units activities, excluding activities related to Fortress Companies: 
 
 | 
 | 
 | 
 | 
 | 
 | 
 
  | 
      | 
  | 
      | 
Weighted  | 
 
  | 
  | 
  | 
  | 
average grant  | 
 
  | 
  | 
Number of shares  | 
  | 
price  | 
 
Unvested balance at December 31, 2020  | 
  | 
 15,507,504  | 
  | 
$  | 
 2.49  | 
 
Restricted stock granted  | 
  | 
 2,330,678  | 
  | 
  | 
 3.17  | 
 
Restricted stock vested  | 
  | 
 (301,492)  | 
  | 
  | 
 2.75  | 
 
Restricted stock units granted  | 
  | 
 1,130,842  | 
  | 
  | 
 4.13  | 
 
Restricted stock units forfeited  | 
  | 
 (96,750)  | 
  | 
  | 
 3.49  | 
 
Restricted stock units vested  | 
  | 
 (493,027)  | 
  | 
  | 
 3.51  | 
 
Unvested balance at September 30, 2021  | 
  | 
 18,077,755  | 
  | 
$  | 
 2.64  | 
 
 
 
 | 
| Schedule of Warrant activities | 
 The following table summarizes Fortress warrant activities, excluding activities related to Fortress Companies: 
 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
Total weighted  | 
  | 
Weighted average  | 
 
  | 
  | 
  | 
  | 
  | 
  | 
  | 
average  | 
  | 
remaining  | 
 
  | 
  | 
Number of  | 
  | 
Weighted average  | 
  | 
 intrinsic  | 
  | 
contractual life  | 
 
  | 
      | 
shares  | 
      | 
exercise price  | 
      | 
value  | 
      | 
(years)  | 
 
Outstanding as of December 31, 2020  | 
   | 
 4,590,621  | 
  | 
$  | 
 3.17  | 
  | 
$  | 
 607,848  | 
   | 
 4.85  | 
 
Expired  | 
  | 
 (60,000)  | 
  | 
  | 
 1.37  | 
  | 
  | 
 —  | 
  | 
  | 
 
Forfeited  | 
  | 
 (25,000)  | 
  | 
  | 
 3.00  | 
  | 
  | 
 —  | 
  | 
  | 
 
Outstanding as of September 30, 2021  | 
   | 
 4,505,621  | 
  | 
$  | 
 3.20  | 
  | 
$  | 
 632,587  | 
   | 
 4.19  | 
 
Exercisable as of September 30, 2021  | 
   | 
 4,370,621  | 
  | 
$  | 
 3.23  | 
  | 
$  | 
 475,087  | 
   | 
 4.11  | 
 
 
 |