Shareholders' Equity - Controlled Equity Offering (Details) - USD ($)			1 Months Ended	6 Months Ended		12 Months Ended
	Apr. 22, 2013	Apr. 18, 2013	Aug. 14, 2017	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2015	Dec. 31, 2016	Jan. 19, 2016
Class of Stock [Line Items]
Common stock aggregate offering price				$ 355			$ 344
Proceeds from the issuance of common stock through controlled equity offering				0	$ 691,187
Cantor Fitzgerald And Company | The Sales Agreement
Class of Stock [Line Items]
Common stock authorized for sale		$ 25,000,000						$ 15,081,494
Commission rate		3.00%
Common stock issued (in shares)	264,831
Stock offering, maximum public float								$ 75,000,000
Proceeds from the issuance of common stock through controlled equity offering					$ 691,187
Recovery of deferred offering costs						$ 48,977
Value of common stock available for sale under agreement				$ 14,300,000
Cantor Fitzgerald And Company | The Sales Agreement | Subsequent Event
Class of Stock [Line Items]
Controlled equity offering lock-up period			60 days
Cantor Fitzgerald And Company | The Sales Agreement | Common Stock
Class of Stock [Line Items]
Common stock issued (in shares)					77,141
Cantor Fitzgerald And Company | The Sales Agreement | Offer and Sale
Class of Stock [Line Items]
Common stock aggregate offering price		$ 17,000,000