Short-Term Investments - Summary of Estimated Fair Value of Short-Term Investments (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	$ 85,579	$ 125,194
Gross Unrealized Gain	206	95
Gross Unrealized Loss	(62)	(6)
Estimated Fair Value	85,723	125,283
Commercial paper
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	17,352	24,147
Gross Unrealized Gain	11	10
Gross Unrealized Loss	0	0
Estimated Fair Value	$ 17,363	$ 24,157
Commercial paper | Maximum
Cash Cash Equivalents And Short Term Investments [Line Items]
Available-for-sale securities, Maturity (in years)	1 year	1 year
U.S. Government-sponsored enterprise
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	$ 20,255	$ 33,073
Gross Unrealized Gain	63	26
Gross Unrealized Loss	0	0
Estimated Fair Value	$ 20,318	$ 33,099
U.S. Government-sponsored enterprise | Maximum
Cash Cash Equivalents And Short Term Investments [Line Items]
Available-for-sale securities, Maturity (in years)	2 years	2 years
U.S. Treasury securities
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	$ 12,721	$ 17,963
Gross Unrealized Gain	93	17
Gross Unrealized Loss	0	(1)
Estimated Fair Value	$ 12,814	$ 17,979
U.S. Treasury securities | Maximum
Cash Cash Equivalents And Short Term Investments [Line Items]
Available-for-sale securities, Maturity (in years)	1 year	2 years
Corporate debt securities
Cash Cash Equivalents And Short Term Investments [Line Items]
Amortized Cost	$ 35,251	$ 50,011
Gross Unrealized Gain	39	42
Gross Unrealized Loss	(62)	(5)
Estimated Fair Value	$ 35,228	$ 50,048
Corporate debt securities | Maximum
Cash Cash Equivalents And Short Term Investments [Line Items]
Available-for-sale securities, Maturity (in years)	2 years	2 years