Stockholders' Equity, Preferred Stock and Common Stock (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Class of Stock Disclosures [Abstract]
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)	29,943,086	4,304,425
Common stock, shares outstanding (in shares)	29,943,086	4,304,425
Series C Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, stated value (in dollars per share)	$ 1,000
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
Preferred stock, shares issued (in shares)	9,968	36,182
Preferred stock, shares outstanding (in shares)	9,968	36,182
Number of common shares issued on conversion of preferred stock (in shares)	9,744,916	1,598,346
Series B Convertible Preferred Stock [Member]
Class of Stock Disclosures [Abstract]
Preferred stock, shares outstanding (in shares)	0	0
Number of common shares issued on conversion of preferred stock (in shares)		467,836