CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues:
Total revenues	$ 685	$ 2,728
Operating expenses:
Research and development	12,720	11,695
General and administrative	4,121	3,666
Loss on fair value remeasurement of contingent consideration	483	234
Total operating expenses	17,324	15,595
Operating loss	(16,639)	(12,867)
Investment and other income, net	101	242
Net loss	$ (16,538)	$ (12,625)
Basic and diluted net loss per common share	$ (0.42)	$ (0.73)
Shares used in calculating basic and diluted net loss per share	39,614	17,406
Comprehensive loss:
Net loss	$ (16,538)	$ (12,625)
Other comprehensive income (loss):
Unrealized loss on marketable securities	(2)	(22)
Comprehensive loss	(16,540)	(12,647)
Product development and licensing agreements
Revenues:
Total revenues	3	2,286
Contracts and grants
Revenues:
Total revenues	$ 682	$ 442