Common Stock (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) Vote $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Aug. 31, 2018 USD ($)	Jul. 30, 2018 USD ($)	Mar. 08, 2018 USD ($)	Aug. 31, 2015 USD ($)
Common Stock [Abstract]
Common stock, shares authorized (in shares) | shares	100,000,000	100,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001	$ 0.0001
Common Stock [Member]
Common Stock [Abstract]
Common stock, voting rights	Each share of common stock has the right to one vote
Number of votes entitled to each share of common stock | Vote	1
Common stock, shares authorized (in shares) | shares	100,000,000
Common stock, par value (in dollars per share) | $ / shares	$ 0.0001
Number of shares of common stock sold (in shares) | shares	1,860,483	7,510,555
Universal Shelf Registration Statement [Member] | Common Stock [Member] | Maximum [Member]
Common Stock [Abstract]
Securities offered for sale, aggregate value | $				$ 100,000		$ 100,000
ATM Agreement [Member] | Common Stock [Member]
Common Stock [Abstract]
Aggregate value of common stock available for offer and sale | $	$ 26,592
Number of shares of common stock sold (in shares) | shares	1,860,483	7,510,555
Average sales price per common share (in dollars per share) | $ / shares	$ 5.84	$ 3.71
Aggregate proceeds from sales of common stock | $	$ 10,866	$ 27,837
Sales commissions, fees and other costs associated with issuance of common stock | $	$ 326	$ 785
ATM Agreement [Member] | Common Stock [Member] | Maximum [Member]
Common Stock [Abstract]
Securities offered for sale, aggregate value | $			$ 50,000		$ 50,000	$ 35,000
Warrants [Member]
Information about warrants outstanding [Abstract]
Number of warrants issued (in shares) | shares	25,000
Exercise price per common share (in dollars per share) | $ / shares	$ 7.0
Expiration date	Apr. 30, 2020