CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Expenses
Research and development	$ 19,797	$ 15,081
General and administrative	11,144	5,394
Restructuring costs	1,025	0
Total operating expenses	31,966	20,475
Loss from operations	(31,966)	(20,475)
Other income (expense), net	(1,117)	228
Change in fair value of warrant liability	(19,799)	0
Loss before income taxes	(52,882)	(20,247)
Income tax expense (benefit)	(23)	39
Net loss for the year	(52,859)	(20,286)
Unrealized loss on available-for-sale investments	13	0
Comprehensive loss for the year	$ (52,872)	$ (20,286)
Basic and diluted net loss per share (in dollars per share)	$ (4.78)	$ (3.00)
Weighted average number of shares used in computing net loss per share, basic and diluted (in shares)	11,057,040	6,762,985