Goodwill and Acquired Intangible Assets - Schedule of Expected Amortization Expense in Future Periods (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	[1]
Goodwill And Intangible Assets Disclosure [Abstract]
2017 (remaining 9 months)	$ 397
2018	528
2019	528
2020	528
2021	528
Thereafter	1,072
Net Book Value	$ 3,581	$ 8,393

[1] The Condensed Consolidated Balance Sheet as of December 31, 2016 has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by generally accepted accounting principles for complete financial statements.