Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets:
Cash equivalents	$ 1,890	$ 13,732
Total assets	72,178	72,474
Liabilities:
Total liabilities		17
Contingent consideration - MuGard
Liabilities:
Contingent consideration - MuGard		17
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	1,890	13,732
Total assets	1,890	13,732
Liabilities:
Total liabilities		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Contingent consideration - MuGard
Liabilities:
Contingent consideration - MuGard		0
Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	0	0
Total assets	70,288	58,742
Liabilities:
Total liabilities		0
Significant Other Observable Inputs (Level 2) | Contingent consideration - MuGard
Liabilities:
Contingent consideration - MuGard		0
Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0	0
Total assets	0	0
Liabilities:
Total liabilities		17
Significant Unobservable Inputs (Level 3) | Contingent consideration - MuGard
Liabilities:
Contingent consideration - MuGard		17
Corporate debt securities
Assets:
Marketable securities	63,488	54,492
Corporate debt securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Marketable securities	0	0
Corporate debt securities | Significant Other Observable Inputs (Level 2)
Assets:
Marketable securities	63,488	54,492
Corporate debt securities | Significant Unobservable Inputs (Level 3)
Assets:
Marketable securities	0	0
U.S. treasury and government agency securities
Assets:
Marketable securities		2,750
U.S. treasury and government agency securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Marketable securities		0
U.S. treasury and government agency securities | Significant Other Observable Inputs (Level 2)
Assets:
Marketable securities		2,750
U.S. treasury and government agency securities | Significant Unobservable Inputs (Level 3)
Assets:
Marketable securities		0
Certificates of deposit
Assets:
Marketable securities	5,800	1,500
Certificates of deposit | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Marketable securities	0	0
Certificates of deposit | Significant Other Observable Inputs (Level 2)
Assets:
Marketable securities	5,800	1,500
Certificates of deposit | Significant Unobservable Inputs (Level 3)
Assets:
Marketable securities	0	$ 0
Commercial paper
Assets:
Marketable securities	1,000
Commercial paper | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Marketable securities	0
Commercial paper | Significant Other Observable Inputs (Level 2)
Assets:
Marketable securities	1,000
Commercial paper | Significant Unobservable Inputs (Level 3)
Assets:
Marketable securities	$ 0