Shareholders’ Equity (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended				9 Months Ended	0 Months Ended	3 Months Ended	9 Months Ended				9 Months Ended			9 Months Ended		0 Months Ended	1 Months Ended				1 Months Ended			0 Months Ended		0 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Aug. 27, 2014	Aug. 26, 2014	Dec. 31, 2013	Sep. 30, 2014 Stock Option	Mar. 31, 2014 Restricted Stock	Sep. 30, 2014 Restricted Stock	Sep. 30, 2014 Restricted Stock Research and development	Sep. 30, 2014 Restricted Stock General and administrative	Sep. 30, 2014 Series C-1 Preferred Stock	Dec. 31, 2013 Series C-1 Preferred Stock	Sep. 30, 2014 Series C-1 Preferred Stock Common Stock	Sep. 30, 2014 Series F Preferred Stock	Dec. 31, 2013 Series F Preferred Stock	Sep. 30, 2014 Series F Preferred Stock Common Stock	Sep. 30, 2014 Consultant Restricted Stock	Sep. 24, 2013 2013 Equity Plan	Sep. 30, 2013 2013 Equity Plan	Sep. 30, 2014 2013 Equity Plan	Aug. 27, 2014 2013 Equity Plan	Jan. 02, 2014 2013 Equity Plan	Sep. 30, 2013 2013 Equity Plan Director	Sep. 30, 2013 One-year Anniversary Date of Grant 2013 Equity Plan	Sep. 30, 2013 One-year Anniversary Date of Grant 2013 Equity Plan Director	Jul. 23, 2014 Underwriting Agreement [Member]	Jul. 23, 2014 IPO [Member]	Jul. 23, 2014 Over-Allotment Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized	100,000,000	100,000,000	100,000,000	12,000,000,000	12,000,000,000
Shares of common stock to be issued and sold in underwriting agreement																										4,800,000		595,000
Price per share of shares sold (usd per share)																											$ 10.50
Proceeds from the underwriting agreement, including additional shares sold, gross																										$ 56.6
Term of option to purchase additional shares																										30 days
Number of additional shares available																												720,000
Proceeds from the underwriting agreement, including additional shares sold, net of cost																										53.1
Issuance costs																										3.5
Preferred stock, shares authorized	8,000,000	8,000,000									11,000	11,000		10,000	10,000
Preferred stock, par value	$ 0.0001	$ 0.0001									$ 0.0001	$ 0.0001		$ 0.0001	$ 0.0001
Shares of common stock issued													5,341,670			129,105	2,976
Shares issued upon conversion, per share											1,724			286
Preferred stock, shares issued											3,917	7,016		2,798	3,250
Shares reserved for future issuance											6,752,908			800,228
Equity plan, term																			10 years
Period of share-based payment awards																			4 years				3 years
Award vesting rights, percentage																								25.00%	33.00%
Automatic annual increase based on outstanding shares of Common Stock as of the last day of the previous year end, percent																		10.00%
Shares available for grant																				576,304	1,100,000	440,441
Stock options granted	137,000	466,900
Weighted average grant date fair value per share of stock options granted	$ 8.38	$ 9.49
Unamortized share-based compensation expense						4.0
Shares canceled upon forfeiture							39,811	7,318
Recognized weighted average period						40 months			16 months	27 months
Unamortized share-based compensation expense									$ 1.9	$ 8.5