Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)
Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 60,700,000	$ 65,134,000
Accumulated deficit	(480,907,000)	(470,111,000)
Working capital	$ 56,300,000
Number of operating segment | Segment	1
Cash and cash equivalents, restricted cash maturity period	Three months or less
Lessee, operating lease, existence of option to extend	true
Lessee, operating lease, existence of option to terminate	true
Impairments of long-lived assets	$ 2,870,000	$ 0
Impairments of right-of-use assets	2,372,024
leasehold improvement assets	$ 498,023
Assembled Workforce [Member]
Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	3 years
Discounted Cash Flows [Member]
Significant Accounting Policies [Line Items]
Right-of-use and leasehold improvement assets, discount rate	0.095
Minimum [Member]
Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives	3 years
Maximum [Member]
Significant Accounting Policies [Line Items]
Property and equipment estimated useful lives	5 years