Nature of Business, Basis of Presentation and Liquidity - Liquidity (Details) $ / shares in Units, $ in Thousands			12 Months Ended
	Jan. 03, 2020 USD ($) director $ / shares shares	Mar. 27, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Accumulated deficit			$ 195,168	$ 153,535
Net loss			32,900	23,138
Net cash used in operating activities			(26,902)	(26,033)
Cash and cash equivalents			$ 3,891	$ 16,284
Preferred stock, proceeds	$ 25,300	$ 14,796
Exclusive Option and License Agreement
Consideration received for rights	$ 3,000
Series A Preferred Stock
Preferred stock, shares issued | shares	1,421,801
Preferred stock par value (per share) | $ / shares	$ 0.001
Sale price per share | $ / shares	$ 10.54
Series B Preferred Stock
Preferred stock, shares issued | shares	1,137,442
Preferred stock par value (per share) | $ / shares	$ 0.001
Sale price per share | $ / shares	10.55
Special Voting Stock
Preferred stock par value (per share) | $ / shares	$ 0.001
Board seats | director	1