Term Loan - Other (Details)		3 Months Ended		6 Months Ended
	Jan. 25, 2019 USD ($) item	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Apr. 30, 2016 USD ($)
Face amount	$ 5,000,000					$ 1,000,000
Interest rate (as a percent)	4.25%	4.50%	3.79%	4.50%	3.66%
Number of equal monthly payments of principal plus accrued interest | item	36
Interest expense		$ 57,000	$ 6,000	$ 99,000	$ 13,000
Prime rate | Maximum
Spread (as a percent)	1.00%