Nature of the Business (Details)			12 Months Ended
	Nov. 10, 2014 $ / shares shares	Oct. 01, 2014	Dec. 31, 2015 shares	Dec. 31, 2014 shares
Note 1 - Nature of the Business (Details) [Line Items]
Stockholders' Equity Note, Reverse Stock Split			On October 1, 2014, the Company effected a 1 for 4.86 reverse share split of its common shares and Series A, B and E redeemable convertible preferred shares. At the time of the consolidation, there were no outstanding Series C and D preferred shares and therefore such series were not included in the consolidation. Accordingly, (i) every 4.86 common shares were combined into one common share, (ii) every 4.86 redeemable Series A, B and E convertible preferred shares were combined into one redeemable convertible preferred share, (iii) the number of common shares into which each outstanding subscription right was exchangeable into common shares were proportionately decreased on a 1 for 4.86 basis, (iv) the number of common shares into which each outstanding option to purchase common shares was exercisable were proportionately decreased on a 1 for 4.86 basis, and (v) the exercise price for each such outstanding option to purchase common shares was proportionately increased on a 1 for 4.86 basis. All of the share numbers, share prices, and exercise prices prior to October 1, 2014 have been adjusted, on a retroactive basis, to reflect this 1 for 4.86 reverse share split.
Preferred Stock, Shares Outstanding	0
Converted from Subscription Rights [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Common stock issued upon conversion of subscription rights	10,201
IPO [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Issuance of common shares, net of issuance costs (in Shares)	4,600,000
Share Price (in Dollars per share) | $ / shares	$ 9.00
Common Stock [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Issuance of common shares, net of issuance costs (in Shares)				5,095,000
Common stock issued upon conversion of preferred stock				7,725,924
Common stock issued upon conversion of subscription rights	10,201
Common Stock [Member] | Private Placement [Member] | Genentech Affiliate [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Issuance of common shares, net of issuance costs (in Shares)	495,000
Share Price (in Dollars per share) | $ / shares	$ 9.00
Common Stock [Member] | Reverse Stock Split [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio		4.86
Series A Preferred Stock [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Preferred Stock, Shares Outstanding				0
Series A Preferred Stock [Member] | Preferred Stock [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Common stock issued upon conversion of preferred stock				(1,151,468)
Series A Preferred Stock [Member] | Preferred Stock [Member] | Reverse Stock Split [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio		4.86
Series B Preferred Stock [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Preferred Stock, Shares Outstanding				0
Series B Preferred Stock [Member] | Preferred Stock [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Common stock issued upon conversion of preferred stock				(994,885)
Series B Preferred Stock [Member] | Preferred Stock [Member] | Reverse Stock Split [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio		4.86
Series E Preferred Stock [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Preferred Stock, Shares Outstanding				0
Series E Preferred Stock [Member] | Preferred Stock [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Common stock issued upon conversion of preferred stock				(4,322,126)
Series E Preferred Stock [Member] | Preferred Stock [Member] | Reverse Stock Split [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio		4.86
Series C Preferred Stock [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Preferred Stock, Shares Outstanding			0	0
Series D Preferred Stock [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Preferred Stock, Shares Outstanding			0	0
Redeemable Convertible Preferred Stock [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Common stock issued upon conversion of preferred stock	7,725,924