Stockholders' Equity Common Stock - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended
	Nov. 27, 2019	Jun. 21, 2019	Jun. 18, 2019	Dec. 31, 2019	Dec. 31, 2018	Jul. 01, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized				200,000,000	200,000,000
Common stock, par value				$ 0.001	$ 0.001
Aggregate net proceeds from offering of common stock				$ 60,527
Sales Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued				128,400
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued				28,818,578
Initial Public Offering ("IPO") [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized						200,000,000
Common stock, par value						$ 0.001
Underwritten Public Offering [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate net proceeds from offering of common stock		$ 4,551	$ 55,976
Underwritten Public Offering [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued		2,151,911	26,666,667
Common stock, share price		$ 2.25	$ 2.25
Underwritten Public Offering [Member] | Common Stock [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option to purchase additional shares of common stock			2,666,666
At The Market Equity Offering Program [Member] | Sales Agreement [Member] | Cowen And Company, LLC [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, par value	$ 0.001
Gross proceeds from sale of common stock	$ 25,000