Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2017

Investments Debt And Equity Securities [Abstract]

Summary of Fair Values of Cash Equivalents, Short-Term Investments and Long-Term Investments Classified as Available-for-Sale Securities

The fair values of cash equivalents, short-term investments, and long-term investments classified as available-for-sale securities, consisted of the following (in thousands):

	December 31, 2017
			Gross Unrealized
	Amortized Cost		Gains		Losses			Estimated Fair Value
Money market funds	$	79,670	$	—	$	—		$	79,670
Corporate bonds		39,330		—		(90	)		39,240
U.S. Government Treasury and agency securities		105,029		—		(290	)		104,739
Total	$	224,029	$	—	$	(380	)	$	223,649

	December 31, 2016
			Gross Unrealized
	Amortized Cost		Gains		Losses			Estimated Fair Value
Money market funds	$	123,536	$	—	$	—		$	123,536
Corporate bonds		207,909		14		(197	)		207,726
Commercial paper		11,970		—		—			11,970
Asset-backed securities		27,712		3		(2	)		27,713
U.S. Government Treasury and agency securities		112,166		10		(245	)		111,931
Total	$	483,293	$	27	$	(444	)	$	482,876

Summary of Inventory

Inventory consists of the following (in thousands):

	December 31,
	2017		2016
Work-in-process	$	737	$	—
Finished goods		20		—
Total inventory	$	757	$	—

Summary of Property and Equipment

Property and equipment, net consists of the following (in thousands):

	December 31,
	2017			2016
Research and development equipment	$	7,696		$	2,154
Furniture and office equipment		2,873			2,595
Computer equipment		2,563			2,013
Software		4,182			3,931
Leasehold improvements		15,085			12,486
Construction-in-progress		429			37
Property and equipment, gross		32,828			23,216
Less accumulated depreciation		(10,991	)		(6,161	)
Property and equipment, net	$	21,837		$	17,055

Accrued Liabilities

Accrued liabilities consists of the following (in thousands):

	December 31,
	2017		2016
Research and clinical study expenses	$	17,141	$	18,593
Payroll and related expenses		26,527		17,226
Repayment liability under collaboration agreement		3,681		13,650
Contract liability		5,986		—
Other		8,092		5,085
Total accrued liabilities	$	61,427	$	54,554