Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues:
Net product sales	$ 36,659	$ 17,277	$ 68,261	$ 28,844
Operating expenses:
Cost of product sales	13,588	5,231	28,550	8,364
Research and development	41,425	30,159	84,397	69,720
General and administrative	9,778	6,209	19,426	13,237
Sales and marketing	23,647	14,531	52,367	28,366
Total operating expenses	88,438	56,130	184,740	119,687
Loss from operations	(51,779)	(38,853)	(116,479)	(90,843)
Other income (expense), net	1,557	183	3,245	(92)
Net loss	(50,222)	(38,670)	(113,234)	(90,935)
Other comprehensive income (loss):
Unrealized gains (losses) on short-term investments	112	17	235	(15)
Comprehensive loss	$ (50,110)	$ (38,653)	$ (112,999)	$ (90,950)
Basic and diluted net loss per share	$ (0.63)	$ (0.54)	$ (1.43)	$ (1.33)
Shares used in computing basic and diluted net loss per share	79,548	71,952	78,987	68,358