The gross cash inflow from the additional capital contribution to the entity.

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Exercise price per share or per unit of warrants or rights outstanding.

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Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares.

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Number of warrants or rights outstanding.

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Face amount or stated value per share of common stock.

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Value of all classes of common stock held by shareholders. May be all or portion of the number of common shares authorized. These shares exclude common shares repurchased by the entity and held as treasury shares.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The cash inflow from the additional capital contribution to the entity.

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Per share or per unit amount of equity securities issued.

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Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended				3 Months Ended			6 Months Ended
	Dec. 21, 2018	May 31, 2020	Oct. 31, 2019	Aug. 31, 2018	Sep. 30, 2017	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Aug. 06, 2018
Stock transactions
Proceeds from public offering of common stock, net of issuance costs									$ 105,689
Par value (per share)						$ 0.00001			$ 0.00001		$ 0.00001
2017 Form S-3
Stock transactions
Maximum aggregate offering price					$ 200,000
2019 Form S-3
Stock transactions
Maximum aggregate offering price			$ 250,000						$ 120,000
Common Stock
Stock transactions
Price (in dollars per share)		$ 14.00
Common stock sold (in shares)		7,000,000				8,050,000			8,050,000
Issuance of common stock upon exercise of Exchange Warrants (in shares)							599,997			599,997
Common Stock \| 2017 Form S-3
Stock transactions
Common stock available for sale						$ 72,000			$ 72,000
Common Stock \| Underwriter overallotment option
Stock transactions
Price (in dollars per share)		$ 14.00
Common stock sold (in shares)		1,050,000
Common Stock \| Private Placement
Stock transactions
Number of warrants exercised						0			0
Common Stock \| 2017 Sales Agreement
Stock transactions
Common stock sold (in shares)		1,232,793			921,684
Proceeds from public offering of common stock, net of issuance costs		$ 105,300			$ 10,500	$ 16,600			$ 16,600
At-the-market offering (ATM)
Stock transactions
Maximum aggregate offering price									$ 57,700
At-the-market offering (ATM) \| 2019 Form S-3
Stock transactions
Maximum aggregate offering price			$ 75,000
At-the-market offering (ATM) \| 2017 Sales Agreement
Stock transactions
Maximum aggregate offering price					$ 50,000
Investors \| Common Stock
Stock transactions
Price (in dollars per share)												$ 8.00
Common stock sold (in shares)				2,750,000
Aggregate gross proceeds												$ 21,700
Investors \| Common Stock \| Private Placement
Stock transactions
Warrants to purchase common stock, number of shares												2,750,000
Exchange Agreement \| Exchanging Stockholders
Stock transactions
Warrants to purchase common stock, number of shares	1,000,000
Common stock exchanged for pre-funded warrants								1,000,000
Par value (per share)	$ 0.00001
Exercise Price (per share)	$ 0.00001
Duration of warrants from date of issuance (in years)	10 years
Equity method investment, ownership percentage	9.99%
Exchange Agreement \| Exchanging Stockholders \| Common Stock
Stock transactions
Number of warrants exercised						600,000			600,000
Issuance of common stock upon exercise of Exchange Warrants (in shares)									599,997
Exchange warrants unexercised						400,000			400,000
Group one \| Common Stock \| Private Placement
Stock transactions
Number of shares to be converted for each warrant												1,375,000
Exercise Price (per share)												$ 10.00
Group two \| Common Stock \| Private Placement
Stock transactions
Number of shares to be converted for each warrant												1,375,000
Exercise Price (per share)												$ 15.00