Stock-based Compensation - Summary of Stock-based Compensation Stock Options Activity (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares
2005 Plan
Stock Option Activity
Number of options outstanding, Beginning of period (in shares) | shares	100,000
Number of options outstanding, Granted (in shares) | shares	0
Number of options outstanding, Exercised (in shares) | shares	(40,000)
Number of options outstanding, Forfeited (in shares) | shares	0
Number of options outstanding, Expired (in shares) | shares	0
Number of options outstanding, Ending of period (in shares) | shares	60,000
Weighted Average Exercise Price
Weighted average exercise price, Outstanding beginning (USD per share) | $ / shares	$ 5.77
Weighted average exercise price, Granted (USD per share) | $ / shares	0
Weighted average exercise price, Exercised (USD per share) | $ / shares	1.60
Weighted average exercise price, Forfeited (USD per share) | $ / shares	0
Weighted average exercise price, Expired (USD per share) | $ / shares	0
Weighted average exercise price, Outstanding ending (USD per share) | $ / shares	$ 6.28
Stock Option Additional Disclosures
Number of options outstanding, Full vested and expected to vest (in shares) | shares	60,000
Number of options outstanding, Vested (in shares) | shares	60,000
Weighted average exercise price, Full vested and expected to vest (USD per share) | $ / shares	$ 6.28
Weighted average exercise price, Vested (USD per share) | $ / shares	$ 6.28
Aggregate intrinsic value, Outstanding | $	$ 241
Aggregate intrinsic value, Fully vested and expected to vest | $	241
Aggregate intrinsic value, Vested | $	$ 241
2010 Plan
Stock Option Activity
Number of options outstanding, Beginning of period (in shares) | shares	220,000
Number of options outstanding, Granted (in shares) | shares	0
Number of options outstanding, Exercised (in shares) | shares	(10,000)
Number of options outstanding, Forfeited (in shares) | shares	0
Number of options outstanding, Expired (in shares) | shares	0
Number of options outstanding, Ending of period (in shares) | shares	210,000
Weighted Average Exercise Price
Weighted average exercise price, Outstanding beginning (USD per share) | $ / shares	$ 7.75
Weighted average exercise price, Granted (USD per share) | $ / shares	0
Weighted average exercise price, Exercised (USD per share) | $ / shares	2.53
Weighted average exercise price, Forfeited (USD per share) | $ / shares	0
Weighted average exercise price, Expired (USD per share) | $ / shares	0
Weighted average exercise price, Outstanding ending (USD per share) | $ / shares	$ 8.00
Stock Option Additional Disclosures
Number of options outstanding, Full vested and expected to vest (in shares) | shares	210,000
Number of options outstanding, Vested (in shares) | shares	210,000
Weighted average exercise price, Full vested and expected to vest (USD per share) | $ / shares	$ 8.00
Weighted average exercise price, Vested (USD per share) | $ / shares	$ 8.00
Aggregate intrinsic value, Outstanding | $	$ 483
Aggregate intrinsic value, Fully vested and expected to vest | $	483
Aggregate intrinsic value, Vested | $	$ 483