Formation and Business of the Company (Details) $ / shares in Units, $ in Thousands		1 Months Ended		12 Months Ended
	Mar. 13, 2019	Aug. 31, 2019 $ / shares shares	Apr. 30, 2019 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($)
Subsequent Event [Line Items]
Accumulated deficit				$ 191,526	$ 139,111
Cash and cash equivalents				39,181	24,990
Available-for-sale investments				69,732
Reverse stock split	0.3704
Payments of deferred offering costs				2,481	233
Accounts receivable				$ 8,601	$ 6,382
IPO
Subsequent Event [Line Items]
Issued and sold common stock (in shares) | shares			6,000,000
Net proceeds			$ 109,119
Stock issued, price per share (in USD per share) | $ / shares			$ 20.00	$ 20.00
IPO - Underwriting Discounts And Commissions
Subsequent Event [Line Items]
Payments of deferred offering costs			$ 8,400
IPO - Other Expenses
Subsequent Event [Line Items]
Payments of deferred offering costs			$ 2,481
Second Public Offering
Subsequent Event [Line Items]
Issued and sold common stock (in shares) | shares		4,200,000
Stock issued, price per share (in USD per share) | $ / shares		$ 39.50
Over-Allotment Option
Subsequent Event [Line Items]
Issued and sold common stock (in shares) | shares		630,000