CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Stockholders' equity:
Preferred stock, shares authorized (in shares)	10,000,000
Preferred stock, par value (in dollars per share)	$ 0.10
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	4,304,425	2,166,898
Common stock, shares outstanding (in shares)	4,304,425	2,166,898
Series B Convertible Preferred Stock [Member]
Stockholders' equity:
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	6,000
Preferred stock, shares outstanding (in shares)	0	6,000
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Series C Convertible Preferred Stock [Member]
Stockholders' equity:
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	36,182	0
Preferred stock, shares outstanding (in shares)	36,182	0
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10