CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Total	Series A Nonconvertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]
BALANCE at Dec. 31, 2013	$ 427,686	$ 2	$ 468	$ 572,401	$ (130,159)	$ (4,368)	$ (10,658)
BALANCE (in shares) at Dec. 31, 2013		200,000	46,825,168				401,501
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income	4,022				4,022
Other comprehensive income (loss)	122					122
Exercise of common stock options, Shares			38,097
Exercise of common stock options, Value	616		1	615
Stock-based employee compensation, net of shares withheld for employee taxes, Shares			2,333
Stock-based employee compensation, net of shares withheld for employee taxes, Value	(54)		0	(54)
Issuance of common stock to Board of Directors and Scientific Advisory Board Shares			20,734
Issuance of common stock to Board of Directors and Scientific Advisory Board Value	526		0	526
Issuance of common stock to employees under an Employee Stock Purchase Plan (ESPP) (in shares)			3,164
Issuance of common stock to employees under an ESPP	86		0	86
BALANCE at Mar. 31, 2014	$ 433,004	$ 2	$ 469	$ 573,574	$ (126,137)	$ (4,246)	$ (10,658)
BALANCE (in shares) at Mar. 31, 2014		200,000	46,889,496				401,501