Common Stock and Stockholders' Equity (Narrative) (Details)	Dec. 31, 2016 vote shares	Dec. 31, 2015 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares outstanding (in shares)	52,924,805	52,669,266
Common stock voting rights per share (vote) | vote	1
Common stock options outstanding (in shares)	8,931,498	5,126,000
Total common shares reserved for future issuance (in shares)	11,244,249
Common stock available for future grant under the 2012 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for future grant under the 2012 Plan (in shares)	718,299
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for future grant under the 2012 Plan (in shares)	1,594,452
Common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares outstanding (in shares)	52,924,805