Warrants (Details) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019 USD ($) $ / shares shares	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2018 USD ($)
Warrants [Abstract]
Share price (in dollars per share) | $ / shares	$ 15.00			$ 15.00
Change in fair value of warrant	$ 0		$ 1,859	$ 0	$ 1,162
Discount Rate [Member]
Warrants [Abstract]
Measurement input of warrants			0.265		0.265
Volatility Rates [Member]
Warrants [Abstract]
Measurement input of warrants			0.9		0.9
Additional Paid-in Capital [Member]
Warrants [Abstract]
Warrant liability reclassified to equity		$ 12,951
Perceptive Credit Opportunities Fund, LP [Member]
Warrants [Abstract]
Number of shares received upon automatic exercise of warrant (in shares) | shares	863,400			863,400
Cash received for warrant exercise				$ 116
Perceptive Credit Opportunities Fund, LP [Member] | Line of Credit [Member]
Warrants [Abstract]
Warrant to purchase senior common equity interest ratio to fully diluted common units	4.50%			4.50%
Purchase price of warrant within first year of the loan	$ 3,000			$ 3,000
Purchase price of warrant after first year	5,000			5,000
Warrant liability, fair value	$ 5,800			$ 5,800