Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		9 Months Ended
	Feb. 28, 2019	Apr. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Class of Stock [Line Items]
Proceeds from issuance of common stock, net of offering costs			$ 118,657	$ 103,259
Firm Commitment Public Underwritten Offer
Class of Stock [Line Items]
Number of shares issued or sold (in shares)		4,500,000
Common stock purchase price (in dollars per share)		$ 21.25
Proceeds from issuance of common stock, net of offering costs		$ 103,000
Over-allotment option
Class of Stock [Line Items]
Number of shares issued or sold (in shares)	825,000	675,000
Common stock purchase price (in dollars per share)	$ 20.00	$ 21.25
Follow-On Equity Offering
Class of Stock [Line Items]
Number of shares issued or sold (in shares)	5,500,000
Common stock purchase price (in dollars per share)	$ 20.00
Proceeds from issuance of common stock, net of offering costs	$ 118,700