Stockholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands				6 Months Ended	12 Months Ended
	Jan. 09, 2020	Jan. 02, 2020	Oct. 29, 2019	Jun. 30, 2020	Dec. 31, 2019	Dec. 30, 2019
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)				5,000,000	5,000,000
Preferred stock, par value (in dollars per share)				$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)				350,000,000	350,000,000
Common stock, par value (in dollars per share)				$ 0.0001	$ 0.0001
Number of shares of stock (in shares)				0	524,097	75,000
Net proceeds of common stock		$ 300			$ 2,700	$ 300
Common stock to be called by warrants (in shares)	818,900
Stock subscription receivable				$ 0	$ 308
Pre-Funded Warrants
Class of Stock [Line Items]
Net proceeds of common stock	$ 6,000
Offering (in dollars per share)	$ 3.9725
Warrants exercisable (in shares)	448,800
Gross proceeds from warrant exercises	$ 6,500
Investor
Class of Stock [Line Items]
Common stock, par value (in dollars per share)	$ 0.0001
Aggregate common stock (in shares)	1,189,000
Offering (in dollars per share)	$ 3.9825
Warrant exercise price (in dollars per share)	$ 3.93
Warrant term	5 years 6 months
Distribution Agreement
Class of Stock [Line Items]
Sale of shares, common stock gross proceeds			$ 5,000
Percentage gross proceeds from the sale of share (as a percent)			3.00%