Non-Cash Share-Based Employee Compensation (Details)	6 Months Ended
	Jun. 30, 2021 USD ($) $ / shares shares
Non-Cash Share-Based Employee Compensation
Outstanding stock options | shares	489,000
Vested stock options | shares	185,800
Nonvested stock options | shares	303,200
Expired stock options | shares	10,000
Outstanding stock options | shares	479,000
Vested stock options | shares	250,600
Nonvested stock options | shares	228,400
Outstanding wgt. avg. exercise price	$ 3.96
Vested wgt. avg. exercise price	4.15
Nonvested wgt. avg. exercise price	3.84
Issued wgt. avg. exercise price	0
Exercised wgt. avg. exercise price	0
Forfeited wgt. avg. exercise price	0
Expired wgt. avg. exercise price	4.55
Outstanding wgt. avg. exercise price	3.94
Vested wgt. avg. exercise price	4.10
Nonvested wgt. avg. exercise price	$ 3.77
Outstanding contractual life, Beginning	7 years 2 months 23 days
Nonvested contractual life, Begining	8 years 2 months 12 days
Vested contractual life, Begining	5 years 7 months 24 days
Outstanding contractual life, Ending	6 years 10 months 17 days
Vested contractual life, Ending	6 years
Nonvested contractual life, Ending	7 years 10 months 2 days
Outstanding grant date fair value	$ 1.51
Vested grant date fair value	1.55
Nonvested grant date fair value	1.49
Issued grant date fair value	0
Exercised grant date fair value	0
Forfeited grant date fair value	0
Expired grant date fair value	1.06
Outstanding grant date fair value	1.52
Vested grant date fair value	1.55
Nonvested grant date fair value	$ 1.48
Outstanding aggregate intrinsic value | $	$ 20,000,000
Vested aggregate intrinsic value | $	20,000,000
Nonvested aggregate intrinsic value | $	0
Issued aggregate intrinsic value | $	0
Forfeited aggregate intrinsic value | $	0
Exercised aggregate intrinsic value | $	0
Outstanding aggregate intrinsic value | $	24,250,000
Vested aggregate intrinsic value | $	24,250,000
Nonvested aggregate intrinsic value | $	$ 0