Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating expenses
Selling, general and administrative	$ (14,475)	$ (9,801)
Research and development	(10,954)	(12,309)
Loss from operations	(25,429)	(22,110)
Other income (expense), net	(312)	(548)
Net loss before income taxes	(25,741)	(22,658)
Income tax expense	(46)	(46)
Net loss	(25,787)	(22,704)
Net loss attributable to common stockholders—basic and diluted	$ (25,787)	$ (22,704)
Net loss per share attributable to common stockholders—basic and diluted (in dollars per share)	$ (0.76)	$ (0.85)
Weighted average number of common shares outstanding—basic and diluted (in shares)	33,777,395	26,723,266
Net loss	$ (25,787)	$ (22,704)
Unrealized gain (loss) on available-for-sale investments	(37)	111
Comprehensive loss	$ (25,824)	$ (22,593)