Stockholders' Equity, Preferred Stock and Common Stock (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Class of Stock Disclosures [Abstract]
Series C Convertible Preferred Stock, shares authorized (in shares)	10,000,000	10,000,000
Series C Convertible Preferred Stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, stated value (in dollars per share)	$ 1,000
Series C Convertible Preferred Stock, shares issued (in shares)	0	2,103
Series C Convertible Preferred Stock, shares outstanding (in shares)	0	2,103
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock shares issued on exercise of options (in shares)	33,801,045	32,932,273
Common stock, shares outstanding (in shares)	33,801,045	32,932,273
Series C Convertible Preferred Shares [Member]
Class of Stock Disclosures [Abstract]
Beneficial ownership percentage	9.99%
Preferred stock conversion price (in dollars per share)	$ 2.69
Number of common shares issuable on conversion of preferred stock (in shares)	15,049,000
Number of common shares issued on conversion of preferred stock (in shares)	782,089	2,923,791