Fair Value of Financial Instruments - Additional Information (Details) - USD ($)			6 Months Ended
	Mar. 07, 2017	Jan. 13, 2016	Jun. 30, 2016	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liability	$ 1,100,000
Money market funds				$ 5,300,000	$ 2,600,000
Redwood City, California [Member] | Level 3 [Member] | Sublease of Excess Space [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, discount rate		20.00%
Essentialis, Inc. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liability	$ 1,100,000
NeoForce, Inc [Member] | NeoForce Group, Inc. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of royalty			$ 153,000
Fair value inputs, discount rate			20.00%
Development Milestone [Member] | Essentialis, Inc. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Probability of development success rate (percent)	15.30%
Revenue milestone in 2023				100,000,000
Revenue milestone in 2025				$ 200,000,000