Common Stock, Common Stock Warrants and Stock Option Plan - Public Offering (Details) $ / shares in Units, $ in Millions	1 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares
Follow-on Offering [Member]
Subsidiary, Sale of Stock [Line Items]
Stock issued (in shares)	5,000,000
Share price (in dollars per share) | $ / shares	$ 4.00
Proceeds from public offering, net of underwriting discounts and commissions | $	$ 18.4
Over-Allotment Option [Member]
Subsidiary, Sale of Stock [Line Items]
Stock issued (in shares)	625,000