Nature of the Business (Details)			3 Months Ended	12 Months Ended
	Nov. 10, 2014 $ / shares shares	Oct. 01, 2014	Mar. 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 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
Preferred Stock, Subscription Rights Outstanding	0
Converted from Convertible Preferred Shares [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Subscribed common stock issued	7,725,924
Converted from Subscription Rights [Member]
Note 1 - Nature of the Business (Details) [Line Items]
Subscribed common stock issued	10,201
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
Subscription rights converted into common shares	10,201
Common Stock [Member] | 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] | 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] | 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] | 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] | 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
Series D Preferred Stock
Note 1 - Nature of the Business (Details) [Line Items]
Preferred Stock, Shares Outstanding			0