Employee Benefit Plans - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands |
12 Months Ended |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
Dec. 31, 2012 |
Dec. 31, 2011 |
Dec. 31, 2010 |
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
|
|
|
|
|
|
|
| Company's contributions to employee saving plan |
$ 0
|
$ 73
|
$ 132
|
|
|
|
|
|
|
|
| Discretionary company's contribition to employee saving plan |
0
|
0
|
36
|
|
|
|
|
|
|
|
| Compensation expense |
$ 1,268
|
$ 2,885
|
$ 4,556
|
|
|
|
|
|
|
|
| Share appreciation rights and stock options |
|
|
|
|
|
|
|
|
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
|
|
|
|
|
|
|
| Method used for the calculation of all stock options awards |
Black-Scholes method
|
|
|
|
|
|
|
|
|
|
| Exercised, shares |
0
|
0
|
0
|
|
|
14,319
|
15,356
|
2,925
|
13,058
|
13,058
|
| Expected term simplified method |
4.5 years
|
|
|
|
|
|
|
|
|
|
| Vesting Period |
3 years
|
|
|
|
|
|
|
|
|
|
| Weighted average time to vest |
2 years
|
|
|
|
|
|
|
|
|
|
| Contractual term of the award |
7 years
|
|
|
|
|
|
|
|
|
|
| Service Conditions |
|
|
|
|
|
|
|
|
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
|
|
|
|
|
|
|
| Expected volatility |
|
|
|
84.71%
|
55.17%
|
|
|
|
|
|
| Risk free rate |
|
|
|
1.81%
|
1.46%
|
|
|
|
|
|
| Estimated compensation cost relating to non-vested service conditions stock option not yet recognized |
$ 0
|
|
|
|
|
|
|
|
|
|
| Estimated compensation cost relating to non-vested service conditions restricted stock and restricted stock units awards not yet recognized |
$ 666
|
|
|
|
|
|
|
|
|
|
| Years to maturity |
2 years 2 months 3 days
|
|
|
|
|
|
|
|
|
|
| Restricted share unit awards |
|
|
|
|
|
|
|
|
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
|
|
|
|
|
|
|
| Expected dividend assumption |
$ 0
|
$ 0
|
$ 0
|
|
|
|
|
|
|
|
| Fair value of stock granted |
|
|
12.7
|
|
|
|
|
|
|
|
| Restricted share unit |
|
|
|
|
|
|
|
|
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
|
|
|
|
|
|
|
| Expected dividend assumption |
$ 0
|
0
|
0
|
|
|
|
|
|
|
|
| Fair value of stock granted |
|
$ 2.84
|
$ 3
|
|
|
|
|
|
|
|
| Tranche - Year 1 | Share appreciation rights and stock options |
|
|
|
|
|
|
|
|
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
|
|
|
|
|
|
|
| Percentage of vesting of the service conditions options, per each year |
33.30%
|
|
|
|
|
|
|
|
|
|
| Tranche - Year 2 | Share appreciation rights and stock options |
|
|
|
|
|
|
|
|
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
|
|
|
|
|
|
|
| Percentage of vesting of the service conditions options, per each year |
33.30%
|
|
|
|
|
|
|
|
|
|
| Tranche - Year 3 | Share appreciation rights and stock options |
|
|
|
|
|
|
|
|
|
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |
|
|
|
|
|
|
|
|
|
|
| Percentage of vesting of the service conditions options, per each year |
33.40%
|
|
|
|
|
|
|
|
|
|