Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets:
Total assets	$ 152,231	$ 188,181
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total assets	5,729	5,842
Significant Other Observable Inputs (Level 2)
Assets:
Total assets	146,502	182,339
Money Market Funds | Cash and Cash Equivalents
Assets:
Total assets	5,497	5,615
Money Market Funds | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash and Cash Equivalents
Assets:
Total assets	5,497	5,615
Short-term Investments - Certificates of Deposits | Short-term Investments
Assets:
Total assets	22,769	20,696
Short-term Investments - Certificates of Deposits | Cash and Cash Equivalents
Assets:
Total assets	1,000	4,070
Short-term Investments - Certificates of Deposits | Significant Other Observable Inputs (Level 2) | Short-term Investments
Assets:
Total assets	22,769	20,696
Short-term Investments - Certificates of Deposits | Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents
Assets:
Total assets	1,000	4,070
Short-term Investments - Commercial Paper | Short-term Investments
Assets:
Total assets	85,185	102,715
Short-term Investments - Commercial Paper | Cash and Cash Equivalents
Assets:
Total assets	22,548	34,860
Short-term Investments - Commercial Paper | Significant Other Observable Inputs (Level 2) | Short-term Investments
Assets:
Total assets	85,185	102,715
Short-term Investments - Commercial Paper | Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents
Assets:
Total assets	22,548	34,860
U.S. Government Bonds | Short-term Investments
Assets:
Total assets	15,000	14,998
U.S. Government Bonds | Cash and Cash Equivalents
Assets:
Total assets		5,000
U.S. Government Bonds | Significant Other Observable Inputs (Level 2) | Short-term Investments
Assets:
Total assets	15,000	14,998
U.S. Government Bonds | Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents
Assets:
Total assets		5,000
Available-for-Sale Investment | Short-term Investments
Assets:
Total assets	232	227
Available-for-Sale Investment | Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term Investments
Assets:
Total assets	$ 232	$ 227