Convertible Preferred Stock (Details) - USD ($)			12 Months Ended
		Oct. 06, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Convertible Preferred Stock [Abstract]
Proceeds			$ 0	$ 52,394,571	$ 14,917,257
Common shares on conversion (in shares)		18,566,856
Preferred stock, shares outstanding (in shares)			0	0
Preferred Stock Warrants [Abstract]
Warrants exercised (in shares)			58,769
Issuance of common stock from exercise of warrants (in shares)			44,032
Warrants exercisable (in shares)			541,415
Warrants Issued in Connection with Loan Agreement [Member]
Preferred Stock Warrants [Abstract]
Number of shares of stock that can be purchased with warrants (in shares)		600,184
Warrants Issued in Connection with Loan Agreement [Member] | Minimum [Member]
Preferred Stock Warrants [Abstract]
Exercise price of warrants (in dollars per share)		$ 5.79
Warrants Issued in Connection with Loan Agreement [Member] | Maximum [Member]
Preferred Stock Warrants [Abstract]
Exercise price of warrants (in dollars per share)		$ 12.10
Convertible Note [Member]
Convertible Preferred Stock [Abstract]
Notes payable converted			$ 100,000
Accrued interest converted			2,645
Convertible Promissory Note [Member]
Convertible Preferred Stock [Abstract]
Notes payable converted			250,000
Accrued interest converted			$ 3,365
Convertible Preferred Stock - Series A [Member]
Convertible Preferred Stock [Abstract]
Number of shares (in shares)									474,014	390,486
Price per share (in dollars per share)									$ 1.00	$ 1.00
Proceeds									$ 474,000	$ 390,000
Common stock conversion price (in dollars per share)									$ 1.00	$ 1.00
Common shares on conversion (in shares)									474,014	390,486
Offer costs									$ 43,000	$ 25,000
Convertible Preferred Stock - Series B [Member]
Convertible Preferred Stock [Abstract]
Number of shares (in shares)								2,333,000
Price per share (in dollars per share)								$ 1.25
Proceeds								$ 2,916,000
Common stock conversion price (in dollars per share)								$ 1.25
Common shares on conversion (in shares)								2,333,000
Offer costs								$ 27,000
Convertible Preferred Stock - Series B [Member] | Convertible Note [Member]
Convertible Preferred Stock [Abstract]
Number of shares (in shares)	[1]							82,116
Price per share (in dollars per share)	[1]							$ 1.25
Proceeds	[1]							$ 103,000
Common stock conversion price (in dollars per share)	[1]							$ 1.25
Common shares on conversion (in shares)	[1]							82,116
Offer costs	[1]							$ 0
Convertible Preferred Stock - Series B-1 [Member]
Convertible Preferred Stock [Abstract]
Number of shares (in shares)							359,935
Price per share (in dollars per share)							$ 1.75
Proceeds							$ 630,000
Common stock conversion price (in dollars per share)							$ 1.75
Common shares on conversion (in shares)							359,935
Offer costs							$ 153,000
Convertible Preferred Stock - Series C [Member]
Convertible Preferred Stock [Abstract]
Number of shares (in shares)						4,631,505
Price per share (in dollars per share)						$ 3.85
Proceeds						$ 17,831,000
Common stock conversion price (in dollars per share)						$ 3.85
Common shares on conversion (in shares)						4,631,505
Offer costs						$ 2,746,612
Dividends [Abstract]
Cumulative dividend rate						8.00%
Convertible Preferred Stock - Series C [Member] | Convertible Promissory Note [Member]
Convertible Preferred Stock [Abstract]
Number of shares (in shares)	[2]					65,809
Price per share (in dollars per share)	[2]					$ 3.85
Proceeds	[2]					$ 253,000
Common stock conversion price (in dollars per share)	[2]					$ 3.85
Common shares on conversion (in shares)	[2]					65,809
Offer costs	[2]					$ 0
Convertible Preferred Stock - Series C-1 [Member]
Convertible Preferred Stock [Abstract]
Number of shares (in shares)					3,558,890
Price per share (in dollars per share)					$ 4.65
Proceeds					$ 16,549,000
Common stock conversion price (in dollars per share)					$ 4.65
Common shares on conversion (in shares)					3,558,890
Offer costs					$ 2,022,025
Dividends [Abstract]
Cumulative dividend rate					8.00%
Convertible Preferred Stock - Series C-2 [Member]
Convertible Preferred Stock [Abstract]
Number of shares (in shares)				12,043,006
Price per share (in dollars per share)				$ 4.65
Proceeds				$ 56,000,000
Common stock conversion price (in dollars per share)				$ 4.65
Common shares on conversion (in shares)				12,043,006
Offer costs				$ 3,782,650
Dividends [Abstract]
Cumulative dividend rate				8.00%

[1] Conversion of $100,000 Note plus accrued interest of $2,645.

[2] Conversion of $250,000 promissory note plus accrued interest of $3,365.