Redeemable Convertible Preferred Stock - Additional Information (Detail)	1 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) $ / shares shares	Jan. 31, 2020 $ / shares shares	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) shares
Temporary Equity [Line Items]
Gross Proceeds from temporary equity			$ 82,544,000	$ 10,949,000
Preferred stock tranche right liability current					$ 300,000
Series A Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Preferred stock per share amount of cumulative dividend | $ / shares			$ 0.08
Preferred stock dividend declared			$ 0
Temporary equity shares authorised | shares	25,000,000		25,000,000		25,000,000
Series B Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Temporary equity issue price per share | $ / shares		$ 2.16867
Net proceeds from temporary equity	$ 8,000,000
Preferred stock per share amount of cumulative dividend | $ / shares			$ 0.17349
Preferred stock dividend declared			$ 0
Preferred stock tranche right liability current	$ 300,000		$ 300,000
Temporary equity shares authorised | shares	29,972,284		29,972,284		29,972,284
Temporary equity shares issued during the period | shares		3,688,898
Series B Redeemable Convertible Preferred Stock [Member] | Conversion Ratio One [Member]
Temporary Equity [Line Items]
Conversion ratio of redeemable covertible preferred stock into common stock	1		1
Series B Redeemable Convertible Preferred Stock [Member] | Conversion Ratio Two [Member]
Temporary Equity [Line Items]
Conversion ratio of redeemable covertible preferred stock into common stock	0.15013		0.15013
Series B Redeemable Convertible Preferred Stock [Member] | Conversion Price One [Member]
Temporary Equity [Line Items]
Redeemable convertible preferred stock conversion price | $ / shares	$ 16.21536		$ 16.21536
Series B Redeemable Convertible Preferred Stock [Member] | Conversion Price Two [Member]
Temporary Equity [Line Items]
Redeemable convertible preferred stock conversion price | $ / shares	14.4451		14.4451
Series C Redeemable Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Temporary equity issue price per share | $ / shares	$ 1.6016		1.6016
Preferred stock per share amount of cumulative dividend | $ / shares			$ 0.128128
Preferred stock dividend declared			$ 0
Temporary equity shares authorised | shares	62,489,557		62,489,557
Series C Redeemable Convertible Preferred Stock [Member] | Series C Preferred Stock Purchase Agreement [Member]
Temporary Equity [Line Items]
Temporary equity issue price per share | $ / shares	$ 1.6016		$ 1.6016
Gross Proceeds from temporary equity			$ 75,000,000
Temporary equity shares authorised | shares	62,489,557		62,489,557
Temporary equity shares issued during the period | shares	46,828,167
Temporary equity unamortised stock issuance costs	$ 400,000		$ 400,000
Series C Redeemable Convertible Preferred Stock [Member] | Series C Preferred Stock Purchase Agreement [Member] | Convertible Notes Payable [Member] | Unsecured Debt [Member]
Temporary Equity [Line Items]
Temporary equity shares issued during the period | shares			6,295,756
Debt instrument converted value In excess of principal			$ 100,000
Debt conversion original debt amount	10,000,000
Temporary equity shares issued during the period	$ 85,100,000