Stockholder's Equity, Stock-Based Compensation Expense and Repurchase Plan - Narrative (Details) - USD ($)	3 Months Ended		14 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 22, 2016	Nov. 04, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Maximum number of shares available for sale through the ATM Program				20,000,000
Number of shares issued or committed for issuance under outstanding stock options	838,582	938,606
Number of shares of restricted stock and shares reserved for restricted stock units outstanding	203,622	253,738
Stock-based compensation expense	$ 634,000	$ 743,000
Stock repurchase amount, authorized amount					$ 25,000,000
Shares repurchased, value			$ 3,000,000
Number of shares repurchased			451,792
Repurchased shares, average price per share (usd per share)			$ 6.41