Shareholders’ Equity (Narrative) (Details) $ / shares in Units, $ in Thousands			1 Months Ended										3 Months Ended		4 Months Ended	12 Months Ended
	Mar. 31, 2014 shares	Jan. 25, 2014 USD ($) shares	Dec. 31, 2016 USD ($) $ / shares shares	Sep. 30, 2016 shares	Jan. 31, 2016 shares	Sep. 30, 2015 USD ($) $ / shares shares	Aug. 31, 2015 USD ($) shares	Apr. 30, 2015 shares	Feb. 28, 2015 shares	Dec. 31, 2014 party shares	Jul. 31, 2014 USD ($) $ / shares shares	Sep. 30, 2013 employee shares	Dec. 31, 2016 USD ($) $ / shares shares	Sep. 30, 2014 shares	Nov. 30, 2015 consultant shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Jul. 31, 2015 shares	Jan. 01, 2014 shares	Dec. 31, 2013 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares authorized (in shares)			8,000,000										8,000,000			8,000,000
Preferred stock, par value (usd per share) | $ / shares			$ 0.0001										$ 0.0001			$ 0.0001
Weighted-average grant date fair values of stock options granted (in dollars per share) | $ / shares																$ 15.33	$ 22.56	$ 9.67
Unamortized share-based compensation expense | $			$ 30,630										$ 30,630			$ 30,630
Recognized weighted average period																	2 years 9 months 18 days
Stock options exercised (in shares)																17,548	51,814	0
Intrinsic value of stock options exercised | $																$ 143	$ 928
Warrants granted to purchase common stock (in shares)										51,000
Warrants issued, number of third party recipients | party										2
Third party share-based compensation expense | $																217	1,086	$ 63
Share-based compensation expense | $																14,546	13,072	9,080
Stock issued during period, value | $																	104,596	53,063
General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $																$ 8,889	$ 8,988	$ 7,811
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued (in shares)							4,000
Number of shares of unvested stock awards (in shares)			542,680							1,279,007			542,680			542,680	1,072,899	1,279,007			1,746,853
Stock issued during period, value | $							$ 92
Common stock canceled upon forfeiture (in shares)	39,811													7,318
Restricted Stock [Member] | General and administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense | $																$ 2,161	$ 4,265	$ 6,856
Unamortized share-based compensation expense | $			$ 409										$ 409			$ 409
Grant One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant vesting period										4 years
Consultant [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued (in shares)		2,976
Stock issued during period, value | $		$ 25
Chief Executive Officer [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant (in shares)			542,680										542,680			542,680
Number of shares of unvested stock awards (in shares)																			1,042,680
Accelerated shares (in shares)			500,000
One-year Anniversary Date of Grant [Member] | Grant One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant vesting rights percentage										25.00%
One-year Anniversary Date of Grant [Member] | Grant Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant vesting rights percentage					100.00%					100.00%
2013 Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity plan, term												10 years
Period of share-based payment awards												4 years
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 (in shares)			1,960,200										1,960,200			1,960,200				440,441
Shares of common stock authorized for issuance (in shares)			4,600,000							1,100,000			4,600,000			4,600,000	3,100,000	1,100,000
Shares of common stock for future issuance (in shares)			4,527,662										4,527,662			4,527,662
2013 Equity Plan [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of share-based payment awards												1 year
2013 Equity Plan [Member] | Consultant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of share-based payment awards									3 years
Stock options granted (in shares)									60,000
Share-based compensation expense | $																$ 46	$ 362
2013 Equity Plan [Member] | Consultant [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)															50,000
Share-based compensation expense | $																$ (66)	$ 73
Number of award recipients | consultant															2
Performance achievement percent													75.00%
Percentage of options canceled													25.00%
2013 Equity Plan [Member] | Chief Financial Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted (in shares)								60,000
2013 Equity Plan [Member] | One-year Anniversary Date of Grant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage												25.00%
2013 Equity Plan [Member] | One-year Anniversary Date of Grant [Member] | Chief Financial Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage								25.00%
2013 Equity Plan [Member] | Share-based Compensation Award, Tranche One [Member] | Chief Financial Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of share-based payment awards								3 years
2013 Equity Plan [Member] | Upon Grant [Member] | Consultant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage									25.00%
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued (in shares)																	2,933,000	5,395,000
Stock options exercised (in shares)																17,000	45,000
Stock issued during period, value | $																		$ 1
Common Stock [Member] | Director [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued (in shares)												79,622
Common Stock [Member] | Chief Executive Officer [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued (in shares)												1,327,048
Common Stock [Member] | Employees [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued (in shares)												336,185
Number of award recipients | employee												3
Series C-1 Convertible Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares authorized (in shares)			11,000										11,000			11,000	11,000
Preferred stock, par value (usd per share) | $ / shares			$ 0.0001										$ 0.0001			$ 0.0001	$ 0.0001
Shares issued upon conversion, per share (in shares)										1,724								1,724
Preferred stock, shares issued (in shares)			3,906										3,906			3,906	3,906
Shares reserved for future issuance (in shares)			6,735,378										6,735,378			6,735,378	6,735,378
Liquidation preference per share (in dollars per share) | $ / shares			$ 1,000										$ 1,000			$ 1,000
Liquidation preference | $			$ 3,906										$ 3,906			$ 3,906	$ 3,906
Series C-1 Convertible Preferred Stock [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued (in shares)																	19,134	5,341,670
Series F Preferred Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Preferred stock, shares authorized (in shares)			10,000										10,000			10,000	10,000
Preferred stock, par value (usd per share) | $ / shares			$ 0.0001										$ 0.0001			$ 0.0001	$ 0.0001
Shares issued upon conversion, per share (in shares)										286								286
Preferred stock, shares issued (in shares)			2,737										2,737			2,737	2,737
Shares reserved for future issuance (in shares)			782,032										782,032			782,032	782,032
Liquidation preference | $			$ 2,737										$ 2,737			$ 2,737	$ 2,737
Series F Preferred Stock [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock issued (in shares)																	17,360	129,105
Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrant granted to purchase common stock (in shares)					17,000
Common Stock [Member] | 2013 Equity Plan [Member] | Consultant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, percentage				25.00%
Stock options granted (in shares)				35,000
Common Stock [Member] | 2013 Equity Plan [Member] | Share-based Compensation Award, Tranche One [Member] | Consultant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of share-based payment awards				1 year
Common Stock [Member] | 2013 Equity Plan [Member] | Share-based Compensation Award, Tranche Two [Member] | Consultant [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of share-based payment awards				3 years
Underwriting Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock to be issued and sold in underwriting agreement (in shares)						2,932,500					5,395,000
Proceeds from the underwriting agreement, including additional shares sold, gross | $						$ 111,400					$ 56,600
Proceeds from the underwriting agreement, including additional shares sold, net of cost | $						104,600					53,100
Issuance costs | $						$ 6,800					$ 3,500
IPO [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Price per share of shares sold (usd per share) | $ / shares						$ 38					$ 10.50