Fair Value (Details Textual) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers of financial assets between Level 1 and Level 2	$ 0.0	$ 0.0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs and techniques	Fair values of corporate bonds and U.S. government agency debt securities were derived from a consensus or weighted-average price based on input of market prices from multiple sources at each reporting period. With regard to commercial paper, all of the securities had high credit ratings and one year or less to maturity; therefore, fair value was derived from accretion of purchase price to face value over the term of maturity or quoted market prices for similar instruments if available.
Contingent Consideration [Member] | Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs and techniques	The fair value of short-term contingent consideration, which is related to the achievement of a technical milestone, has been estimated using situation-based modeling, which considers the probability-weighted present value of the expected payout amount. Significant assumptions include the Company's expectations with regard to the likelihood and timing of achievement of the related technical milestone and a discount rate of 2.9%. The fair value of long-term contingent consideration, which is related to achievement of revenue targets, has been estimated using a Monte Carlo simulation to simulate future performance of the acquired business under a risk-neutral framework; significant assumptions include a risk-adjusted discount rate of 10.2% and revenue volatility of 8.0%.