Stock Benefit Plans, Stock-Based Compensation and Equity Transactions - Summary Common Stock Reserved for Future Issuance (Detail) - shares	Dec. 31, 2016	Oct. 04, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	2,650,000
Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance		950,000
Warrants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	8,000
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	1,155,000
Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	1,092,000
Authorized for future grant under 2016 Plan | Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	395,000