The Company and Basis of Presentation - Additional Information (Details) $ / shares in Units, $ in Thousands		3 Months Ended
	Apr. 12, 2016 USD ($) $ / shares shares	Mar. 31, 2017 USD ($) Segment $ / shares shares	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) $ / shares shares
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of operating segments | Segment		1
Offering costs			$ 98
Capital stock, shares authorized | shares	510,000,000
Common stock, shares authorized | shares	500,000,000	500,000,000		500,000,000
Preferred stock, shares authorized | shares	10,000,000	10,000,000		10,000,000
Common stock, par value | $ / shares	$ 0.0001	$ 0.0001		$ 0.0001
Preferred stock, par value | $ / shares	$ 0.0001	$ 0.0001		$ 0.0001
Preferred stock, shares outstanding | shares		0		0
Working capital		$ 56,300
Accumulated deficit		(51,524)		$ (45,277)
Cash, cash equivalents and marketable securities		$ 57,900
Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Proceeds from issuance of common stock upon initial public offering, net	$ 47,300
IPO
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Convertible preferred stock, terms of conversion		Ratio of one share of common stock for each share of convertible preferred stock
Convertible preferred stock converted into common stock | shares	7,172,496
Convertible preferred stock reclassified into common stock and additional paid-in-capital	$ 58,311
IPO | Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued | shares	5,481,940
Public offering price | $ / shares	$ 10.00
Underwriting discounts and commissions	$ 3,800
Offering costs	$ 3,700
Underwriters' Over-allotment Option | Common Stock
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued | shares	481,940