Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Assets
Long-term investments	$ 3,215	$ 0
Liabilities
Contingent consideration	3,065	2,953	$ 3,251	$ 3,126
Recurring
Assets
Cash and cash equivalents	26,416	31,799
Short-term investments	58,475	59,035
Long-term investments	3,215
Total Assets	88,106	90,834
Liabilities
Liability-classified options	58	253
Contingent consideration	3,065	2,953
Total Liabilities	3,123	3,206
Recurring | Level 1
Assets
Cash and cash equivalents	26,416	31,799
Short-term investments	58,475	59,035
Long-term investments	3,215
Total Assets	88,106	90,834
Liabilities
Liability-classified options	0	0
Contingent consideration	0	0
Total Liabilities	0	0
Recurring | Level 2
Assets
Cash and cash equivalents	0	0
Short-term investments	0	0
Long-term investments	0
Total Assets	0	0
Liabilities
Liability-classified options	0	0
Contingent consideration	0	0
Total Liabilities	0	0
Recurring | Level 3
Assets
Cash and cash equivalents	0	0
Short-term investments	0	0
Long-term investments	0
Total Assets	0	0
Liabilities
Liability-classified options	58	253
Contingent consideration	3,065	2,953
Total Liabilities	$ 3,123	$ 3,206