CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Non-cash share-based compensation expense	$ 11,440	$ 13,594	$ 12,822
Research and development expense
Non-cash share-based compensation expense	5,145	6,204	5,520
General and administrative expense
Non-cash share-based compensation expense	$ 6,295	$ 7,390	$ 7,302