Consolidated Statements of Shareholders' Equity (USD $) In Thousands, except Share data	Total	Common stock [Member]	Subscription Receivable [Member]	Additional paid-in capital [Member]	Accumulated deficit [Member]
Beginning balance at Dec. 31, 2012	$ 38,331	$ 26	$ (2,004)	$ 112,384	$ (72,075)
Beginning balance, shares at Dec. 31, 2012	26,229,909	26,229,909
Stock-based compensation expense	928			928
Warrants exercised	298			298
Warrants exercised, shares		46,837
Subscription received	2,004		2,004
Issuance of common stock for exclusive collaboration channel agreement	6,406	2		6,404
Issuance of common stock for exclusive collaboration channel agreement, shares		1,243,781
Net loss	(24,981)				(24,981)
Ending balance at Sep. 30, 2013	$ 22,986	$ 28		$ 120,014	$ (97,056)
Ending balance, shares at Sep. 30, 2013	27,520,527	27,520,527