Summary of Significant Accounting Policies - Schedule of Fair Value of Level 3 Instruments (Details) - Convertible Preferred Stock Warrant Liability $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Convertible preferred stock warrant liability — beginning balance	$ 9,990
Change in fair value of preferred stock warrant liability	735
Convertible preferred stock warrant liability — ending balance	$ 10,725