Summary of Significant Accounting Policies - Summary of reconciliation of shares used to determine net loss per share (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Summary of Significant Accounting Policies
Net income (loss)	$ 39	$ 2,667	$ (460)	$ (15,169)
Weighted average number of shares - basic	42,656,510	42,618,391	42,637,945	42,608,396
Weighted average number of shares outstanding - diluted	43,680,265	42,618,391	42,637,945	42,608,396