Fair Value Measurements (Narrative) (Details)			1 Months Ended	12 Months Ended
	Apr. 07, 2014 $ / shares shares	Mar. 18, 2014	Jun. 30, 2014 shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($)	Apr. 24, 2015 $ / shares shares	Apr. 01, 2014 $ / shares shares	Dec. 31, 2012 USD ($)
Class of Stock [Line Items]
Available-for-sale Securities					$ 0
Contingent consideration liabilities				$ 0	11,448,000
Change in fair value of contingent consideration				306,000	66,000	$ 0
Stock Issued During Period Shares, Stock Warrants Net Exercised | shares			12,587
Change in fair value of preferred stock warrant liabilities				0	732,000	4,121,000
Recurring
Class of Stock [Line Items]
Contingent consideration liabilities					11,448,000
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Class of Stock [Line Items]
Contingent consideration liabilities					0
Recurring | Significant Other Observable Inputs (Level 2)
Class of Stock [Line Items]
Contingent consideration liabilities					0
Recurring | Significant Unobservable Inputs (Level 3)
Class of Stock [Line Items]
Contingent consideration liabilities				0	11,448,000	0			$ 0
Change in fair value of contingent consideration				306,000	66,000	0
Nonrecurring
Class of Stock [Line Items]
Asset Impairment Charges				$ 0	0	0
iSocket
Class of Stock [Line Items]
Business Combination, Contingent Consideration, Threshold Trading Days to Determine Number of Shares				10 days
Contingent consideration, shares issued | shares				585,170
iSocket | Recurring | Significant Unobservable Inputs (Level 3)
Class of Stock [Line Items]
Change in fair value of contingent consideration				$ 0	11,382,000	0
Chango
Class of Stock [Line Items]
Business Combination, Contingent Consideration, Shares Held in Escrow | shares							126,098
Business Combination, Contingent Consideration, Threshold Trading Days to Determine Number of Shares				10 days
Business Combination, Contingent Consideration, Stock Price Trigger | $ / shares							$ 18.77
Contingent consideration, shares issued | shares				971,481
Chango | Recurring | Significant Unobservable Inputs (Level 3)
Class of Stock [Line Items]
Change in fair value of contingent consideration				$ 16,171,000	0	$ 0
Money Market Funds [Member] | Recurring
Class of Stock [Line Items]
Available-for-sale Securities				19,257,000	55,963,000
Money Market Funds [Member] | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Class of Stock [Line Items]
Available-for-sale Securities				19,257,000	55,963,000
Money Market Funds [Member] | Recurring | Significant Other Observable Inputs (Level 2)
Class of Stock [Line Items]
Available-for-sale Securities				0	0
Money Market Funds [Member] | Recurring | Significant Unobservable Inputs (Level 3)
Class of Stock [Line Items]
Available-for-sale Securities				$ 0	$ 0
Series C warrants
Class of Stock [Line Items]
Class of warrant or right, outstanding | shares								845,867
Convertible preferred stock warrants
Class of Stock [Line Items]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares	25,174
Common stock warrants
Class of Stock [Line Items]
Stock Issued During Period, Shares, Conversion of Convertible Securities | shares	286,055
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right | shares	12,587
Common Stock
Class of Stock [Line Items]
Stockholders' Equity Note, Stock Split, Conversion Ratio		0.5
Stock Issued During Period, Shares, Conversion of Convertible Securities | shares					14,696,000
Share Price | $ / shares	$ 15							$ 15.00