CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Accounts receivable, allowances (in dollars)	$ 1,256,000	$ 1,255,000
Interest rate (as a percent)	3.00%	3.00%
Series A 3% Redeemable Convertible Preferred Stock, par value (in dollars per share)	$ 0.001	$ 0.001
Series A 3% Redeemable Convertible Preferred Stock, Authorized shares	100,000	100,000
Series A 3% Redeemable Convertible Preferred Stock, Issued shares	0	75,000
Series A 3% Redeemable Convertible Preferred Stock, outstanding shares	0	75,000
Series A 3% Redeemable Convertible Preferred Stock, Redemption value (in dollars)	$ 0	$ 87,089,000
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, Authorized shares	4,900,000	4,900,000
Preferred stock, Issued shares	0	0
Preferred stock, outstanding shares	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, Authorized shares	75,000,000	75,000,000
Common stock, Issued shares	38,408,000	32,385,000
Common stock, Outstanding shares	34,489,000	28,466,000
Treasury stock, shares	3,919,000	3,919,000