Common Stock (Reconciliation of Common Shares Issued and Additional Disclosures) (Details)		12 Months Ended
	Nov. 09, 2009 series $ / shares shares	Dec. 31, 2017 $ / shares shares	Dec. 31, 2016 $ / shares shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Common stock, shares authorized (in shares)	80,000,000	80,000,000	80,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001	$ 0.0001
Preferred stock. shares authorized (in shares)	100,000	100,000	100,000
Preferred stock, minimum number of series authorized | series	1
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001	$ 0.0001
Increase (Decrease) in Stockholders' Equity
Shares issued at the beginning of the year (in shares)		59,684,669	56,220,214
Issued in sale of common stock (in shares)		0	2,450,339
Issued in acquisition (in shares)		0	247,764
Issued in payment of accrued liability (in shares)		0	20,000
Issued as restricted stock award grants (in shares)		275,029	632,240
Issued upon exercise of stock options (in shares)		663,288	114,112
Shares issued at the end of the year (in shares)		60,622,986	59,684,669