Shareholders' Equity - Textual (Details) - USD ($)		9 Months Ended
	Aug. 13, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Class of Stock [Line Items]
Exercise of stock options, common stock issued (in shares)		123,000	499,671
Weighted average exercise price, exercised (in USD per share)		$ 1.88	$ 1.62
Treasury stock (in shares)		12,253,502		12,253,502
Treasury stock, shares held at cost		$ 18,929,915		$ 18,929,915
Common stock, par value (USD per share)		$ 0.001		$ 0.001
Open Market Sale Agreement
Class of Stock [Line Items]
Common stock, par value (USD per share)	$ 0.001
Sale of stock, authorized offering amount	$ 50,000,000.0
Sale of stock, percentage of commissions paid of gross proceeds from sale of each share	3.00%
Sale of stock, reimbursable legal expenses	$ 50,000
Sale of stock, termination amount under agreement, total	$ 50,000,000.0