Stock Benefit Plans and Equity Transactions - Summary Common Stock Reserved for Future Issuance (Details) shares in Thousands	Jun. 30, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	35,031
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	3,313
Unvested restricted share awards
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	2,139
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	360
Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	2,022
Convertible Notes
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	988
Warrants Outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	20,932
Merger shares issuable
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	174
Merger contingently issuable
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	1,330
Authorized for Future Grant Under the Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock reserved for future issuance	3,773