Redeemable Convertible Preferred Stock (Details) - USD ($)		12 Months Ended
	Dec. 23, 2019	Dec. 31, 2019	Dec. 31, 2018
Temporary Equity
Warrant exercise price (per share)		$ 0.75	$ 0.08
Aggregate gross proceeds	$ 3,900,000	$ 10,072,000
Gross proceeds	$ 6,200,000
Common stock trading Price	$ 7.60
Common stock trading Price, Number of trading days	20 days
Common stock trading Price, Number of trading days Subsequent to closing	30 days
Aggregate gross proceeds	$ 87,600,000
Baker Bros. Advisors LP
Temporary Equity
Warrant exercise price (per share)			$ 3.76
Deemed Dividend	28,000,000
Preferred Stock Warrant
Temporary Equity
Preferred Shares		263,521
Aggregate Purchase Price		$ 45,000,272
Series B1 Warrants
Temporary Equity
Gross proceeds received	10,100,000
Estimated fair values	2,600,000
Future Tranche Rights
Temporary Equity
Estimated fair values	$ 35,500,000
Series B1 redeemable convertible preferred stock (Note 7); Designated — 278 shares, Issued and outstanding — 24 and 0 shares at December 31, 2019 and December 31, 2018, respectively
Temporary Equity
Sale of redeemable convertible preferred stock	23,684	23,684,000
Series B1 redeemable convertible preferred stock (Note 7); Designated — 278 shares, Issued and outstanding — 24 and 0 shares at December 31, 2019 and December 31, 2018, respectively | Common Stock Warrant
Temporary Equity
Warrant to purchase common stock	2,368,400
Warrant exercise price (per share)	$ 1.52
Series B1 redeemable convertible preferred stock (Note 7); Designated — 278 shares, Issued and outstanding — 24 and 0 shares at December 31, 2019 and December 31, 2018, respectively | Preferred Stock Warrant
Temporary Equity
Warrant to purchase common stock	23,684
Warrant exercise price (per share)	$ 152
Series B2 Redeemable Convertible Preferred Stock
Temporary Equity
Expiration period	9 months
Series B2 Redeemable Convertible Preferred Stock | Common Stock Warrant
Temporary Equity
Warrant to purchase common stock	9,868,500
Warrant exercise price (per share)	$ 1.52
Series B2 Redeemable Convertible Preferred Stock | Preferred Stock Warrant
Temporary Equity
Warrant to purchase common stock	98,685
Warrant exercise price (per share)	$ 152
Preferred Shares		98,685
Share Price		$ 152
Aggregate Purchase Price		$ 15,000,120
Series B3 Redeemable Convertible Preferred Stock
Temporary Equity
Expiration period	15 months
Series B3 Redeemable Convertible Preferred Stock | Common Stock Warrant
Temporary Equity
Warrant to purchase common stock	6,593,440
Warrant exercise price (per share)	$ 1.82
Series B3 Redeemable Convertible Preferred Stock | Preferred Stock Warrant
Temporary Equity
Warrant to purchase common stock	65,934
Warrant exercise price (per share)	$ 182.00
Preferred Shares		82,418
Share Price		$ 182
Aggregate Purchase Price		$ 15,000,076
Series B4 Redeemable Convertible Preferred Stock
Temporary Equity
Expiration period	21 months
Series B4 Redeemable Convertible Preferred Stock | Preferred Stock Warrant
Temporary Equity
Preferred Shares		82,418
Share Price		$ 182
Aggregate Purchase Price		$ 15,000,076