Description of Business - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Place of incorporation	Arizona
Year of incorporation	2002
Place of reincorporation	Delaware
Date of reincorporation	2015-03
Accumulated deficit	$ (211,825)	$ (207,171)
Cash and cash equivalents	14,042	8,417
Restricted cash	2,001
Short-term investments	11,625	16,915
Net losses	(6,026)	(28,873)
Net cash used in operations	$ (30,218)	$ (17,198)