Redeemable Convertible Preferred Stock - Additional Information (Details)			1 Months Ended				12 Months Ended
	Dec. 19, 2019	Jul. 10, 2018	May 31, 2020	Feb. 29, 2020 USD ($) $ / shares shares	Jul. 31, 2018 USD ($) shares	Aug. 31, 2015 USD ($) Tranche	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 shares	Mar. 31, 2018 USD ($)
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issuance costs | $							$ 0	$ 2,582,000
Convertible stock, voting rights description							Each holder of shares of Preferred Stock was entitled to the number of votes equal to the number of shares of common stock into which such shares could have been converted and had voting rights and powers equal to the voting rights and powers of the common stock, and except as provided by law or by other provisions of the Company’s Certificate of Incorporation, as amended, could have voted together with the common stock as a single class on an as-converted basis on all matters as to which holders of common stock have the right to vote.
Convertible preferred stock, terms of conversion							Shares of the Preferred Stock were convertible at any time at the option of the holder into such number of shares as is determined by dividing the original issuance price by the conversion price in effect at the time.
Reverse stock split, conversion ratio			0.13986014				0.1399
Series C Preferred Stock Purchase Agreement
Temporary Equity [Line Items]
Redeemable convertible preferred stock redemption terms							All outstanding shares of Preferred Stock shall be redeemed by the Company at a price equal to the original issuance price per share, plus any dividends declared but unpaid, in three annual installments commencing not more than sixty (60) days after receipt by the Company at any time on or after five years from the Series C Preferred original issuance date, December 19, 2019, a written notice from the holders of a majority of the shares of Preferred Stock.
Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares authorized							0
Redeemable convertible preferred stock, shares outstanding							0
Series A Preferred Stock
Temporary Equity [Line Items]
Redeembale convertaible preferred stock dividend rate		8.00%
Series A Preferred Stock | Series A Preferred Stock Purchase Agreement
Temporary Equity [Line Items]
Redeemable convertible preferred stock, purchase amount | $						$ 45,000,000				$ 11,000,000
Number of tranches | Tranche						3
Redeemable convertible preferred stock, shares issued								56,000,000
Cash proceeds from redeemable convertible preferred stock | $								$ 56,000,000
Series B Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares authorized							0	49,501,221
Redeemable convertible preferred stock, shares outstanding							0	49,501,221	49,501,221
Redeemable convertible preferred stock, shares issued							0	49,501,221
Redeemable convertible preferred stock conversion price per share | $ / shares							$ 9.843405
Redeemable convertible preferred stock liquidation price per share | $ / shares							$ 1.3767
Series B Redeemable Convertible Preferred Stock | Series B Preferred Stock Purchase Agreement
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issued					49,500,000
Cash proceeds from redeemable convertible preferred stock | $					$ 68,100,000
Series B Redeemable Convertible Preferred Stock | Series B Preferred Stock Purchase Agreement | Maximum
Temporary Equity [Line Items]
Redeemable convertible preferred stock, purchase amount | $					$ 70,000,000
Series B Redeemable Convertible Preferred Stock | Series C Preferred Stock Purchase Agreement
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issued								26,400,000
Cash proceeds from redeemable convertible preferred stock | $								$ 48,200,000
Series B Redeemable Convertible Preferred Stock | Series C Preferred Stock Purchase Agreement | Novartis
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares authorized								10,900,000
Cash proceeds from redeemable convertible preferred stock | $								$ 20,000,000
Percentage of outstanding shares of common stock on fully diluted basis							6.10%	7.40%
Series B Redeemable Convertible Preferred Stock | Series C Preferred Stock Purchase Agreement | Maximum
Temporary Equity [Line Items]
Redeemable convertible preferred stock, purchase amount | $								$ 80,500,000
Series C Redeemable Convertible Preferred Stock | Series C Preferred Stock Purchase Agreement
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares issued				28,500,000
Cash proceeds from redeemable convertible preferred stock | $				$ 52,200,000
Redeemable convertible preferred stock, cash received price per share | $ / shares				$ 1.83
Redeemable convertible preferred stock, shares issuance costs | $				$ 200,000
Series A Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares authorized							0	56,000,000
Redeemable convertible preferred stock, shares outstanding							0	56,000,000	56,000,000
Redeemable convertible preferred stock, shares issued							0	56,000,000
Redeemable convertible preferred stock conversion price per share | $ / shares							$ 7.15
Redeemable convertible preferred stock liquidation price per share | $ / shares							$ 1.00
Series C Redeemable Convertible Preferred Stock
Temporary Equity [Line Items]
Redeemable convertible preferred stock, shares authorized							0	44,000,000
Redeemable convertible preferred stock, shares outstanding							0	26,360,745
Redeemable convertible preferred stock, shares issued							0	26,360,745
Redeemable convertible preferred stock conversion price per share | $ / shares							$ 13.0845
Redeemable convertible preferred stock liquidation price per share | $ / shares							$ 1.83
Series B Preferred Stock | Series B Preferred Stock Purchase Agreement
Temporary Equity [Line Items]
Redeembale convertaible preferred stock dividend rate		8.00%
Series A, Series B and Series C Preferred | Series C Preferred Stock Purchase Agreement
Temporary Equity [Line Items]
Redeembale convertaible preferred stock dividend rate	8.00%