Note 13 - Condensed Quarterly Financial Data (Unaudited) (Details) - Quarterly Financial Data (USD $)
In Thousands, except Per Share data, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
2014      
Operating expenses $ 50,835 $ 41,223 $ 28,499
Net loss (49,963) (38,759) (3,415)
First Quarter [Member]      
2014      
Operating expenses 7,160 [1] 7,991 [2]  
Net loss (9,616) [1],[3] (8,288) [2],[4]  
Net loss per share — basic and diluted (in Dollars per share) $ (0.14) $ (0.14)  
Second Quarter [Member]      
2014      
Operating expenses 7,797 [1] 18,047 [2]  
Net loss (6,032) [1],[3] (16,398) [2],[4]  
Net loss per share — basic and diluted (in Dollars per share) $ (0.09) $ (0.28)  
Third Quarter [Member]      
2014      
Operating expenses 8,020 [1] 7,602 [2]  
Net loss (6,736) [1],[3] (7,710) [2],[4]  
Net loss per share — basic and diluted (in Dollars per share) $ (0.09) $ (0.12)  
Fourth Quarter [Member]      
2014      
Operating expenses 27,858 [1] 7,583 [2]  
Net loss $ (27,578) [1],[3] $ (6,363) [2],[4]  
Net loss per share — basic and diluted (in Dollars per share) $ (0.30) $ (0.09)  
[1] Operating expenses and net loss for the three months ended December 31, 2014 includes an upfront fee of $20.0 million paid to Array in connection with our license agreement in December 2014 (see Note 8).
[2] Operating expenses and net loss for the three months ended June 30, 2013 includes an upfront fee of $10.0 million paid to Array upon initiation of a collaboration agreement that the Company entered into in May 2013 (see Note 8).
[3] Net loss for the three months ended March 31, June 30, September 30 and December 31, 2014 includes change in fair value of warrants income (expense) of approximately $(2.5) million, $1.7 million, $1.3 million and $0.3 million respectively (see Note 3).
[4] Net loss for the three months ended March 31, June 30, September 30 and December 31, 2013 includes change in fair value of warrants income (expense) of approximately $(0.3) million, $1.6 million, $(0.2) million and $1.2 million respectively (see Note 3).