CONDENSED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS
Alliance revenue	$ 378	$ 294
Operating expenses:
Research and development	11,485	9,296
General and administrative	4,081	3,916
Total operating expenses	15,566	13,212
Loss from operations	(15,188)	(12,918)
Other income (expense):
Interest income	153	120
Interest expense	(16)	(23)
Foreign currency exchange loss	(6)	(2)
Net loss	$ (15,057)	$ (12,823)
Basic and diluted net loss per common share (Note 13)	$ (0.10)	$ (0.11)
Shares used in computing basic and diluted net loss per common share	149,100	121,284
Net loss	$ (15,057)	$ (12,823)
Other comprehensive gain (loss):
Unrealized gain on available-for-sale securities	16	134
Comprehensive loss	$ (15,041)	$ (12,689)