Balance Sheet Account Details (Summary of Accrued Expenses) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued clinical study costs	$ 3,371	$ 2,430
Accrued manufacturing costs	1,775	1,823
Accrued other	1,750	1,972
Total accrued expenses	$ 9,572	$ 8,485

Amount of expenses incurred but not yet paid classified as other, due within one year or the normal operating cycle, if longer.

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