Stock Benefit Plans and Equity Transactions - Summary Common Stock Reserved for Future Issuance (Details) shares in Thousands	Mar. 31, 2019 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	35,566
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	4,670
Unvested Restricted Stock Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	3,761
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	223
Series A Convertible Preferred Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	164
Warrants Outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	22,302
Distributor And Development Services Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	3,985
Authorized for future grant under the company equity plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	461