Subsequent Events (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	1 Months Ended	3 Months Ended	12 Months Ended
	Jul. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Subsequent Events [Abstract]
Common Stock sold in public offering (in shares)	9,775	8,750	9,800
Common stock offering price		$ 4.60	$ 4.40
Proceeds from public offering of common stock, net of underwriting discounts and commissions and offering expenses	$ 40,100,000	$ 37,500,000	$ 40,078,000	$ 23,348,000	$ 0
Shelf registration established		150,000,000
Superseded registration		$ 31,700,000